644533416 has 64 divisors (see below), whose sum is σ = 1868227200. Its totient is φ = 205501824.

The previous prime is 644533391. The next prime is 644533453. The reversal of 644533416 is 614335446.

644533416 is a `hidden beast` number, since 644 + 5 + 3 + 3 + 4 + 1 + 6 = 666.

It is a Harshad number since it is a multiple of its sum of digits (36).

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, 59901 + ... + 69836.

It is an arithmetic number, because the mean of its divisors is an integer number (29191050).

Almost surely, 2^644533416 is an apocalyptic number.

It is an amenable number.

644533416 is an abundant number, since it is smaller than the sum of its proper divisors (1223693784).

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

644533416 is a wasteful number, since it uses less digits than its factorization.

644533416 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 129775 (or 129765 counting only the distinct ones).

The product of its digits is 103680, while the sum is 36.

The square root of 644533416 is about 25387.6626730387. The cubic root of 644533416 is about 863.8038713771.

The spelling of 644533416 in words is "six hundred forty-four million, five hundred thirty-three thousand, four hundred sixteen".