623644 has 12 divisors (see below), whose sum is σ = 1247344. Its totient is φ = 267264.

The previous prime is 623641. The next prime is 623653. The reversal of 623644 is 446326.

623644 is an admirable number.

It is a hoax number, since the sum of its digits (25) coincides with the sum of the digits of its distinct prime factors.

It is an Ulam number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (623641) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 11109 + ... + 11164.

2⁶²³⁶⁴⁴ is an apocalyptic number.

It is an amenable number.

623644 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

623644 is a wasteful number, since it uses less digits than its factorization.

623644 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 22284 (or 22282 counting only the distinct ones).

The product of its digits is 3456, while the sum is 25.

The square root of 623644 is about 789.7113396679. The cubic root of 623644 is about 85.4369198322.

The spelling of 623644 in words is "six hundred twenty-three thousand, six hundred forty-four".