6400656 has 30 divisors (see below), whose sum is σ = 17913350. Its totient is φ = 2133504.

The previous prime is 6400637. The next prime is 6400657. The reversal of 6400656 is 6560046.

6400656 is a `hidden beast` number, since 6 + 4 + 0 + 0 + 656 = 666.

It can be written as a sum of positive squares in only one way, i.e., 6170256 + 230400 = 2484^2 + 480^2 .

It is an Ulam number.

6400656 is a modest number, since divided by 656 gives 64 as remainder.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6400657) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 22081 + ... + 22368.

Almost surely, 2^6400656 is an apocalyptic number.

It is an amenable number.

6400656 is an abundant number, since it is smaller than the sum of its proper divisors (11512694).

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

6400656 is a wasteful number, since it uses less digits than its factorization.

6400656 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 44463 (or 44454 counting only the distinct ones).

The product of its (nonzero) digits is 4320, while the sum is 27.

The square root of 6400656 is about 2529.9517781966. The cubic root of 6400656 is about 185.6698966325.

It can be divided in two parts, 6400 and 656, that added together give a square (7056 = 84²).

The spelling of 6400656 in words is "six million, four hundred thousand, six hundred fifty-six".