644152320 has 264 divisors, whose sum is σ = 2552101344. Its totient is φ = 147161088.

The previous prime is 644152309. The next prime is 644152339. The reversal of 644152320 is 23251446.

644152320 is a `hidden beast` number, since 644 + 15 + 2 + 3 + 2 + 0 = 666.

It is a super-2 number, since 2×644152320² = 829864422722764800, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 321562 + ... + 323558.

Almost surely, 2^644152320 is an apocalyptic number.

644152320 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 644152320, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1276050672).

644152320 is an abundant number, since it is smaller than the sum of its proper divisors (1907949024).

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

644152320 is a wasteful number, since it uses less digits than its factorization.

644152320 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2035 (or 2014 counting only the distinct ones).

The product of its (nonzero) digits is 5760, while the sum is 27.

The square root of 644152320 is about 25380.1560278892. The cubic root of 644152320 is about 863.6335894883.

The spelling of 644152320 in words is "six hundred forty-four million, one hundred fifty-two thousand, three hundred twenty".