644052692 has 6 divisors (see below), whose sum is σ = 1127092218. Its totient is φ = 322026344.

The previous prime is 644052679. The next prime is 644052713. The reversal of 644052692 is 296250446.

It can be written as a sum of positive squares in only one way, i.e., 509585476 + 134467216 = 22574^2 + 11596^2 .

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 80506583 + ... + 80506590.

It is an arithmetic number, because the mean of its divisors is an integer number (187848703).

Almost surely, 2^644052692 is an apocalyptic number.

It is an amenable number.

644052692 is a deficient number, since it is larger than the sum of its proper divisors (483039526).

644052692 is a wasteful number, since it uses less digits than its factorization.

644052692 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 161013177 (or 161013175 counting only the distinct ones).

The product of its (nonzero) digits is 103680, while the sum is 38.

The square root of 644052692 is about 25378.1932375022. The cubic root of 644052692 is about 863.5890624818.

The spelling of 644052692 in words is "six hundred forty-four million, fifty-two thousand, six hundred ninety-two".