644697092 has 24 divisors (see below), whose sum is σ = 1225769496. Its totient is φ = 294916608.

The previous prime is 644697083. The next prime is 644697121. The reversal of 644697092 is 290796446.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 4910656 + 639786436 = 2216^2 + 25294^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 48983 + ... + 60734.

It is an arithmetic number, because the mean of its divisors is an integer number (51073729).

Almost surely, 2^644697092 is an apocalyptic number.

It is an amenable number.

644697092 is a deficient number, since it is larger than the sum of its proper divisors (581072404).

644697092 is a wasteful number, since it uses less digits than its factorization.

644697092 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 109847 (or 109845 counting only the distinct ones).

The product of its (nonzero) digits is 653184, while the sum is 47.

The square root of 644697092 is about 25390.8860026585. The cubic root of 644697092 is about 863.8769847294.

The spelling of 644697092 in words is "six hundred forty-four million, six hundred ninety-seven thousand, ninety-two".