644616616446 has 64 divisors (see below), whose sum is σ = 1563351701760. Its totient is φ = 195257774880.

The previous prime is 644616616393. The next prime is 644616616463.

644616616446 is a `hidden beast` number, since 6 + 4 + 4 + 6 + 16 + 616 + 4 + 4 + 6 = 666.

644616616446 is nontrivially palindromic in base 10.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a junction number, because it is equal to n+sod(n) for n = 644616616392 and 644616616401.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 1224925 + ... + 1670231.

It is an arithmetic number, because the mean of its divisors is an integer number (24427370340).

Almost surely, 2^644616616446 is an apocalyptic number.

644616616446 is a gapful number since it is divisible by the number (66) formed by its first and last digit.

644616616446 is an abundant number, since it is smaller than the sum of its proper divisors (918735085314).

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

644616616446 is a wasteful number, since it uses less digits than its factorization.

644616616446 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 447766 (or 447760 counting only the distinct ones).

The product of its digits is 11943936, while the sum is 54.

The spelling of 644616616446 in words is "six hundred forty-four billion, six hundred sixteen million, six hundred sixteen thousand, four hundred forty-six".