644109888 has 28 divisors (see below), whose sum is σ = 1704207920. Its totient is φ = 214703232.

The previous prime is 644109887. The next prime is 644109911. The reversal of 644109888 is 888901446.

It is a Harshad number since it is a multiple of its sum of digits (48).

It is not an unprimeable number, because it can be changed into a prime (644109883) by changing a digit.

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 in 3 ways as a sum of consecutive naturals, for example, 1677178 + ... + 1677561.

Almost surely, 2^644109888 is an apocalyptic number.

It is an amenable number.

644109888 is an abundant number, since it is smaller than the sum of its proper divisors (1060098032).

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

644109888 is a wasteful number, since it uses less digits than its factorization.

644109888 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3354754 (or 3354744 counting only the distinct ones).

The product of its (nonzero) digits is 442368, while the sum is 48.

The square root of 644109888 is about 25379.3200854554. The cubic root of 644109888 is about 863.6146258032.

The spelling of 644109888 in words is "six hundred forty-four million, one hundred nine thousand, eight hundred eighty-eight".