644192612 has 18 divisors (see below), whose sum is σ = 1311392502. Its totient is φ = 276082464.

The previous prime is 644192599. The next prime is 644192629. The reversal of 644192612 is 216291446.

It can be written as a sum of positive squares in only one way, i.e., 375429376 + 268763236 = 19376^2 + 16394^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1643153 + ... + 1643544.

It is an arithmetic number, because the mean of its divisors is an integer number (72855139).

Almost surely, 2^644192612 is an apocalyptic number.

It is an amenable number.

644192612 is an abundant number, since it is smaller than the sum of its proper divisors (667199890).

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

644192612 is a wasteful number, since it uses less digits than its factorization.

644192612 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3286715 (or 3286706 counting only the distinct ones).

The product of its digits is 20736, while the sum is 35.

The square root of 644192612 is about 25380.9497852228. The cubic root of 644192612 is about 863.6515959949.

The spelling of 644192612 in words is "six hundred forty-four million, one hundred ninety-two thousand, six hundred twelve".