numclassify 0.1.1

The most comprehensive Python library for number classification — 3000+ number types

numclassify

The most comprehensive Python library for number classification — 3000+ number types, zero dependencies.

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Why numclassify?

Most number-theory libraries — labmath, eulerlib, pyntlib — answer computational questions: factor this, find the GCD, generate primes up to N.

numclassify answers a different question: what kind of number is this?

• 153 → Armstrong, Narcissistic, Harshad, Triangular, Abundant…
• 1729 → Taxicab (Hardy-Ramanujan), Zeisel, Carmichael…
• 28 → Perfect, Triangular, Hexagonal, Semiprime…

Over 3000 named number types, instant lookup, no external dependencies.

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Installation

pip install numclassify

Or clone and install in editable mode:

git clone https://github.com/aratrikghosh2011-tech/numclassify.git
cd numclassify
pip install -e .

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Quick Start

import numclassify as nc

# Boolean checks
nc.is_prime(17)          # True
nc.is_armstrong(153)     # True
nc.is_perfect(28)        # True

# All true properties of a number
nc.get_true_properties(1729)
# ['taxicab', 'zeisel', 'carmichael', 'odd', 'composite',
#  'deficient', 'squarefree', 'cubefree', 'powerful_not_perfect_power']

# Search a range
nc.find_in_range(nc.is_armstrong, 1, 10000)
# [1, 2, 3, 4, 5, 6, 7, 8, 9, 153, 370, 371, 407, 1634, 8208, 9474]

# Pretty-print everything about a number
nc.print_properties(153)
# ┌─────────────────────────────────────────┐
# │  Properties of 153                      │
# ├─────────────────────────────────────────┤
# │  armstrong         ✓                    │
# │  harshad           ✓                    │
# │  triangular        ✓                    │
# │  ...                                    │
# └─────────────────────────────────────────┘

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CLI

numclassify ships with a fully-featured command-line interface.

Check a number:

$ numclassify check 1729
1729 properties:
  taxicab         ✓
  carmichael      ✓
  zeisel          ✓
  odd             ✓
  deficient       ✓
  squarefree      ✓

JSON output (pipe-friendly):

$ numclassify check 153 --json
{"armstrong": true, "harshad": true, "triangular": true, "abundant": true, ...}

Find numbers of a type:

$ numclassify find armstrong --limit 10
1, 2, 3, 4, 5, 6, 7, 8, 9, 153

Filter a range:

$ numclassify range 1 20 --filter prime
2, 3, 5, 7, 11, 13, 17, 19

List all registered types in a category:

$ numclassify list --category primes
twin_prime, mersenne_prime, sophie_germain_prime, safe_prime,
wilson_prime, fermat_prime, ... (41 total)

Get info about a type:

$ numclassify info armstrong
Name:        armstrong
Category:    digital_invariants
Description: A number equal to the sum of its digits each raised to the power
             of the number of digits. Also called narcissistic numbers.
OEIS:        A005188
Examples:    1, 2, 3, 153, 370, 371, 407, 1634, 8208, 9474

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Number Categories

Category	Count	Examples
Polygonal (figurate)	998	Triangular, Square, Pentagonal … Chiliagonal
Centered Polygonal	998	Centered Triangular, Centered Hexagonal …
Prime families	41	Twin, Mersenne, Sophie Germain, Wilson, Safe…
Digital invariants	10	Armstrong, Spy, Harshad, Disarium, Happy, Neon…
Divisor-based	27	Perfect, Abundant, Weird, Amicable, Practical…
Sequences	15	Fibonacci, Lucas, Catalan, Bell, Padovan…
Powers	13	Perfect Square, Taxicab, Sum of Two Squares…
Number theory	14	Evil, Carmichael, Keith, Autobiographical…
Combinatorial	10	Factorial, Primorial, Subfactorial, Catalan…
Recreational	5	Kaprekar, Automorphic, Palindrome…
Total	3000+

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Adding Your Own Number Type

The @register decorator lets you plug in custom types in 6 lines:

from numclassify import register

@register(name="my_type", category="custom")
def is_my_type(n: int) -> bool:
    return n > 0 and n % 7 == 0 and str(n)[0] == "4"

# Now works everywhere
import numclassify as nc
nc.is_my_type(49)              # False  (doesn't start with 4)
nc.is_my_type(42)              # True
nc.get_true_properties(42)     # [..., 'my_type', ...]

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API Reference

Function	Description
is_prime(n)	Returns True if n is a standard prime
is_armstrong(n)	Returns True if n is a narcissistic/Armstrong number
get_all_properties(n)	Dict of every registered type → True/False
get_true_properties(n)	List of only the properties that are True
print_properties(n)	Pretty-prints a formatted property table to stdout
find_in_range(fn, lo, hi)	All integers in [lo, hi] where fn returns True
find_all_in_range(lo, hi)	Dict mapping every number in range to its true properties
count_properties(n)	Count of how many types apply to n
most_special_in_range(lo, hi)	The number in [lo, hi] with the most true properties

Full API docs: github.com/aratrikghosh2011-tech/numclassify

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Requirements

• Python 3.8 or higher
• Zero external dependencies

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License

MIT © 2026 Aratrik Ghosh