401556681 has 12 divisors (see below), whose sum is σ = 583065600. Its totient is φ = 266301720.

The previous prime is 401556667. The next prime is 401556691. The reversal of 401556681 is 186655104.

401556681 is a `hidden beast` number, since 4 + 0 + 15 + 566 + 81 = 666.

It is not a de Polignac number, because 401556681 - 2¹¹ = 401554633 is a prime.

It is a super-2 number, since 2×401556681² = 322495536111471522, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (401556691) 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 11 ways as a sum of consecutive naturals, for example, 115081 + ... + 118518.

It is an arithmetic number, because the mean of its divisors is an integer number (48588800).

Almost surely, 2^401556681 is an apocalyptic number.

It is an amenable number.

401556681 is a deficient number, since it is larger than the sum of its proper divisors (181508919).

401556681 is a wasteful number, since it uses less digits than its factorization.

401556681 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 233796 (or 233793 counting only the distinct ones).

The product of its (nonzero) digits is 28800, while the sum is 36.

The square root of 401556681 is about 20038.8792351269. The cubic root of 401556681 is about 737.7608727983.

The spelling of 401556681 in words is "four hundred one million, five hundred fifty-six thousand, six hundred eighty-one".