644434566032646 has 32 divisors (see below), whose sum is σ = 1433299765564800. Its totient is φ = 214628079187080.

The previous prime is 644434566032617. The next prime is 644434566032701. The reversal of 644434566032646 is 646230665434446.

644434566032646 is a `hidden beast` number, since 6 + 4 + 4 + 4 + 3 + 4 + 566 + 0 + 3 + 2 + 64 + 6 = 666.

It is a super-2 number, since 2×644434566032646² (a number of 30 digits) 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 15 ways as a sum of consecutive naturals, for example, 5095570176 + ... + 5095696643.

It is an arithmetic number, because the mean of its divisors is an integer number (44790617673900).

Almost surely, 2^{644434566032646} is an apocalyptic number.

644434566032646 is an abundant number, since it is smaller than the sum of its proper divisors (788865199532154).

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

644434566032646 is a wasteful number, since it uses less digits than its factorization.

644434566032646 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10191268001 (or 10191267995 counting only the distinct ones).

The product of its (nonzero) digits is 716636160, while the sum is 63.

The spelling of 644434566032646 in words is "six hundred forty-four trillion, four hundred thirty-four billion, five hundred sixty-six million, thirty-two thousand, six hundred forty-six".