644863848 has 32 divisors (see below), whose sum is σ = 1619092800. Its totient is φ = 214030208.

The previous prime is 644863783. The next prime is 644863859. The reversal of 644863848 is 848368446.

It is a nude number because it is divisible by every one of its digits.

It is a self number, because there is not a number n which added to its sum of digits gives 644863848.

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, 52068 + ... + 63251.

It is an arithmetic number, because the mean of its divisors is an integer number (50596650).

Almost surely, 2^644863848 is an apocalyptic number.

It is an amenable number.

644863848 is an abundant number, since it is smaller than the sum of its proper divisors (974228952).

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

644863848 is a wasteful number, since it uses less digits than its factorization.

644863848 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 115561 (or 115557 counting only the distinct ones).

The product of its digits is 3538944, while the sum is 51.

The square root of 644863848 is about 25394.1695670483. The cubic root of 644863848 is about 863.9514611792.

The spelling of 644863848 in words is "six hundred forty-four million, eight hundred sixty-three thousand, eight hundred forty-eight".