401561631 has 32 divisors (see below), whose sum is σ = 621783040. Its totient is φ = 259028280.

The previous prime is 401561627. The next prime is 401561653. The reversal of 401561631 is 136165104.

401561631 is a `hidden beast` number, since 4 + 0 + 15 + 616 + 31 = 666.

It is not a de Polignac number, because 401561631 - 2² = 401561627 is a prime.

It is a super-2 number, since 2×401561631² = 322503486982760322, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 401561595 and 401561604.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (401561621) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 64836 + ... + 70758.

It is an arithmetic number, because the mean of its divisors is an integer number (19430720).

Almost surely, 2^401561631 is an apocalyptic number.

401561631 is a deficient number, since it is larger than the sum of its proper divisors (220221409).

401561631 is an frugal number, since it uses more digits than its factorization.

401561631 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5975 (or 5957 counting only the distinct ones).

The product of its (nonzero) digits is 2160, while the sum is 27.

The square root of 401561631 is about 20039.0027446477. The cubic root of 401561631 is about 737.7639042519.

The spelling of 401561631 in words is "four hundred one million, five hundred sixty-one thousand, six hundred thirty-one".