646442856 has 40 divisors (see below), whose sum is σ = 1810640370. Its totient is φ = 215480736.

The previous prime is 646442851. The next prime is 646442869. The reversal of 646442856 is 658244646.

It can be written as a sum of positive squares in only one way, i.e., 470456100 + 175986756 = 21690^2 + 13266^2 .

It is not an unprimeable number, because it can be changed into a prime (646442851) by changing a digit.

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 9 ways as a sum of consecutive naturals, for example, 498151 + ... + 499446.

Almost surely, 2^646442856 is an apocalyptic number.

It is an amenable number.

646442856 is an abundant number, since it is smaller than the sum of its proper divisors (1164197514).

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

646442856 is a wasteful number, since it uses less digits than its factorization.

646442856 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 997615 (or 997602 counting only the distinct ones).

The product of its digits is 1105920, while the sum is 45.

The square root of 646442856 is about 25425.2405298357. The cubic root of 646442856 is about 864.6560410893.

The spelling of 646442856 in words is "six hundred forty-six million, four hundred forty-two thousand, eight hundred fifty-six".