644351516 has 6 divisors (see below), whose sum is σ = 1127615160. Its totient is φ = 322175756.

The previous prime is 644351507. The next prime is 644351557. The reversal of 644351516 is 615153446.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 80543936 + ... + 80543943.

It is an arithmetic number, because the mean of its divisors is an integer number (187935860).

Almost surely, 2^644351516 is an apocalyptic number.

It is an amenable number.

644351516 is a deficient number, since it is larger than the sum of its proper divisors (483263644).

644351516 is a wasteful number, since it uses less digits than its factorization.

644351516 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 161087883 (or 161087881 counting only the distinct ones).

The product of its digits is 43200, while the sum is 35.

The square root of 644351516 is about 25384.0799715097. The cubic root of 644351516 is about 863.7226029205.

The spelling of 644351516 in words is "six hundred forty-four million, three hundred fifty-one thousand, five hundred sixteen".