400656 has 40 divisors (see below), whose sum is σ = 1098144. Its totient is φ = 125440.

The previous prime is 400651. The next prime is 400657. The reversal of 400656 is 656004.

It is not an unprimeable number, because it can be changed into a prime (400651) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 571 + ... + 1061.

2⁴⁰⁰⁶⁵⁶ is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 400656, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (549072).

400656 is an abundant number, since it is smaller than the sum of its proper divisors (697488).

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

400656 is a wasteful number, since it uses less digits than its factorization.

400656 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 519 (or 513 counting only the distinct ones).

The product of its (nonzero) digits is 720, while the sum is 21.

The square root of 400656 is about 632.9739331126. The cubic root of 400656 is about 73.7208867182.

The spelling of 400656 in words is "four hundred thousand, six hundred fifty-six".