644321232 has 60 divisors (see below), whose sum is σ = 1847202084. Its totient is φ = 209533440.

The previous prime is 644321177. The next prime is 644321243. The reversal of 644321232 is 232123446.

644321232 is a `hidden beast` number, since 6 + 443 + 212 + 3 + 2 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 157854096 + 486467136 = 12564^2 + 22056^2 .

It is a hoax number, since the sum of its digits (27) coincides with the sum of the digits of its distinct prime factors.

It is a nude number because it is divisible by every one of its digits.

It is a junction number, because it is equal to n+sod(n) for n = 644321196 and 644321205.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 48663 + ... + 60470.

Almost surely, 2^644321232 is an apocalyptic number.

It is an amenable number.

644321232 is an abundant number, since it is smaller than the sum of its proper divisors (1202880852).

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

644321232 is a wasteful number, since it uses less digits than its factorization.

644321232 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 109188 (or 109179 counting only the distinct ones).

The product of its digits is 6912, while the sum is 27.

The square root of 644321232 is about 25383.4834488886. The cubic root of 644321232 is about 863.7090712873.

Adding to 644321232 its reverse (232123446), we get a palindrome (876444678).

The spelling of 644321232 in words is "six hundred forty-four million, three hundred twenty-one thousand, two hundred thirty-two".