646888408 has 48 divisors (see below), whose sum is σ = 1274719680. Its totient is φ = 307440000.

The previous prime is 646888399. The next prime is 646888423. The reversal of 646888408 is 804888646.

It is a super-2 number, since 2×646888408² = 836929224809548928, which contains 22 as substring.

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 11 ways as a sum of consecutive naturals, for example, 922458 + ... + 923158.

It is an arithmetic number, because the mean of its divisors is an integer number (26556660).

Almost surely, 2^646888408 is an apocalyptic number.

It is an amenable number.

646888408 is a deficient number, since it is larger than the sum of its proper divisors (627831272).

646888408 is a wasteful number, since it uses less digits than its factorization.

646888408 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 860 (or 795 counting only the distinct ones).

The product of its (nonzero) digits is 2359296, while the sum is 52.

The square root of 646888408 is about 25434.0010222537. The cubic root of 646888408 is about 864.8546462970.

Subtracting from 646888408 its sum of digits (52), we obtain a square (646888356 = 25434²).

The spelling of 646888408 in words is "six hundred forty-six million, eight hundred eighty-eight thousand, four hundred eight".