644732 has 12 divisors (see below), whose sum is σ = 1230936. Its totient is φ = 293040.

The previous prime is 644731. The next prime is 644747. The reversal of 644732 is 237446.

It is a happy number.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 644732.

It is not an unprimeable number, because it can be changed into a prime (644731) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 7283 + ... + 7370.

It is an arithmetic number, because the mean of its divisors is an integer number (102578).

2⁶⁴⁴⁷³² is an apocalyptic number.

It is an amenable number.

644732 is a deficient number, since it is larger than the sum of its proper divisors (586204).

644732 is a wasteful number, since it uses less digits than its factorization.

644732 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14668 (or 14666 counting only the distinct ones).

The product of its digits is 4032, while the sum is 26.

The square root of 644732 is about 802.9520533631. The cubic root of 644732 is about 86.3892576379.

The spelling of 644732 in words is "six hundred forty-four thousand, seven hundred thirty-two".