644823848 has 16 divisors (see below), whose sum is σ = 1209336480. Its totient is φ = 322334128.

The previous prime is 644823847. The next prime is 644823857. The reversal of 644823848 is 848328446.

It is not an unprimeable number, because it can be changed into a prime (644823847) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 41165 + ... + 54627.

It is an arithmetic number, because the mean of its divisors is an integer number (75583530).

Almost surely, 2^644823848 is an apocalyptic number.

It is an amenable number.

644823848 is a deficient number, since it is larger than the sum of its proper divisors (564512632).

644823848 is a wasteful number, since it uses less digits than its factorization.

644823848 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19456 (or 19452 counting only the distinct ones).

The product of its digits is 1179648, while the sum is 47.

The square root of 644823848 is about 25393.3819724746. The cubic root of 644823848 is about 863.9335975774.

The spelling of 644823848 in words is "six hundred forty-four million, eight hundred twenty-three thousand, eight hundred forty-eight".