644861048 has 32 divisors (see below), whose sum is σ = 1304002560. Its totient is φ = 297198720.

The previous prime is 644861033. The next prime is 644861093. The reversal of 644861048 is 840168446.

It is a junction number, because it is equal to n+sod(n) for n = 644860996 and 644861014.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 74633 + ... + 82823.

It is an arithmetic number, because the mean of its divisors is an integer number (40750080).

Almost surely, 2^644861048 is an apocalyptic number.

It is an amenable number.

644861048 is an abundant number, since it is smaller than the sum of its proper divisors (659141512).

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

644861048 is a wasteful number, since it uses less digits than its factorization.

644861048 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8967 (or 8963 counting only the distinct ones).

The product of its (nonzero) digits is 147456, while the sum is 41.

The square root of 644861048 is about 25394.1144362232. The cubic root of 644861048 is about 863.9502107511.

The spelling of 644861048 in words is "six hundred forty-four million, eight hundred sixty-one thousand, forty-eight".