646427808 has 72 divisors (see below), whose sum is σ = 1979696628. Its totient is φ = 198899712.

The previous prime is 646427791. The next prime is 646427809. The reversal of 646427808 is 808724646.

It can be written as a sum of positive squares in 2 ways, for example, as 641710224 + 4717584 = 25332^2 + 2172^2 .

It is a tau number, because it is divible by the number of its divisors (72).

It is not an unprimeable number, because it can be changed into a prime (646427809) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 82585 + ... + 90072.

Almost surely, 2^646427808 is an apocalyptic number.

It is an amenable number.

646427808 is an abundant number, since it is smaller than the sum of its proper divisors (1333268820).

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

646427808 is a wasteful number, since it uses less digits than its factorization.

646427808 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 172686 (or 172675 counting only the distinct ones).

The product of its (nonzero) digits is 516096, while the sum is 45.

The square root of 646427808 is about 25424.9446017096. The cubic root of 646427808 is about 864.6493318368.

The spelling of 646427808 in words is "six hundred forty-six million, four hundred twenty-seven thousand, eight hundred eight".