40644 has 18 divisors (see below), whose sum is σ = 102830. Its totient is φ = 13536.

The previous prime is 40639. The next prime is 40693. The reversal of 40644 is 44604.

40644 is digitally balanced in base 2 and base 4, because in such bases it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in only one way, i.e., 26244 + 14400 = 162^2 + 120^2 .

It is a tau number, because it is divible by the number of its divisors (18).

It is a hoax number, since the sum of its digits (18) coincides with the sum of the digits of its distinct prime factors.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a plaindrome in base 13.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 40644.

It is an unprimeable number.

40644 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 529 + ... + 600.

2⁴⁰⁶⁴⁴ is an apocalyptic number.

It is an amenable number.

40644 is an abundant number, since it is smaller than the sum of its proper divisors (62186).

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

40644 is a wasteful number, since it uses less digits than its factorization.

40644 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1139 (or 1134 counting only the distinct ones).

The product of its (nonzero) digits is 384, while the sum is 18.

The square root of 40644 is about 201.6035713969. The cubic root of 40644 is about 34.3820800843.

The spelling of 40644 in words is "forty thousand, six hundred forty-four".