644931139446 has 64 divisors (see below), whose sum is σ = 1565493143040. Its totient is φ = 195180714720.

The previous prime is 644931139427. The next prime is 644931139453.

644931139446 is a `hidden beast` number, since 64 + 4 + 9 + 3 + 1 + 139 + 446 = 666.

644931139446 is nontrivially palindromic in base 10.

644931139446 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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 = 644931139392 and 644931139401.

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, 243130 + ... + 1161453.

It is an arithmetic number, because the mean of its divisors is an integer number (24460830360).

Almost surely, 2^644931139446 is an apocalyptic number.

644931139446 is a gapful number since it is divisible by the number (66) formed by its first and last digit.

644931139446 is an abundant number, since it is smaller than the sum of its proper divisors (920562003594).

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

644931139446 is a wasteful number, since it uses less digits than its factorization.

644931139446 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1405378 (or 1405372 counting only the distinct ones).

The product of its digits is 6718464, while the sum is 54.

The spelling of 644931139446 in words is "six hundred forty-four billion, nine hundred thirty-one million, one hundred thirty-nine thousand, four hundred forty-six".