644215848 has 32 divisors (see below), whose sum is σ = 1640930400. Its totient is φ = 210686528.

The previous prime is 644215811. The next prime is 644215879. The reversal of 644215848 is 848512446.

It is a hoax number, since the sum of its digits (42) coincides with the sum of the digits of its distinct prime factors.

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, 251958 + ... + 254501.

It is an arithmetic number, because the mean of its divisors is an integer number (51279075).

Almost surely, 2^644215848 is an apocalyptic number.

It is an amenable number.

644215848 is an abundant number, since it is smaller than the sum of its proper divisors (996714552).

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

644215848 is a wasteful number, since it uses less digits than its factorization.

644215848 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 506521 (or 506517 counting only the distinct ones).

The product of its digits is 245760, while the sum is 42.

The square root of 644215848 is about 25381.4075259825. The cubic root of 644215848 is about 863.6619798288.

The spelling of 644215848 in words is "six hundred forty-four million, two hundred fifteen thousand, eight hundred forty-eight".