644522332 has 48 divisors (see below), whose sum is σ = 1234548000. Its totient is φ = 293255424.

The previous prime is 644522321. The next prime is 644522371. The reversal of 644522332 is 233225446.

It is a junction number, because it is equal to n+sod(n) for n = 644522294 and 644522303.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 504078 + ... + 505354.

It is an arithmetic number, because the mean of its divisors is an integer number (25719750).

Almost surely, 2^644522332 is an apocalyptic number.

It is an amenable number.

644522332 is a deficient number, since it is larger than the sum of its proper divisors (590025668).

644522332 is a wasteful number, since it uses less digits than its factorization.

644522332 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1558 (or 1556 counting only the distinct ones).

The product of its digits is 34560, while the sum is 31.

The square root of 644522332 is about 25387.4443770932. Note that the first 3 decimals coincide. The cubic root of 644522332 is about 863.7989197554.

Adding to 644522332 its reverse (233225446), we get a palindrome (877747778).

The spelling of 644522332 in words is "six hundred forty-four million, five hundred twenty-two thousand, three hundred thirty-two".