31601631 has 4 divisors (see below), whose sum is σ = 42135512. Its totient is φ = 21067752.

The previous prime is 31601629. The next prime is 31601651. The reversal of 31601631 is 13610613.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 13610613 = 3 ⋅4536871.

It is not a de Polignac number, because 31601631 - 2¹ = 31601629 is a prime.

It is a super-2 number, since 2×31601631² = 1997326163720322, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 31601598 and 31601607.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31601651) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5266936 + ... + 5266941.

It is an arithmetic number, because the mean of its divisors is an integer number (10533878).

Almost surely, 2^31601631 is an apocalyptic number.

31601631 is a deficient number, since it is larger than the sum of its proper divisors (10533881).

31601631 is a wasteful number, since it uses less digits than its factorization.

31601631 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10533880.

The product of its (nonzero) digits is 324, while the sum is 21.

The square root of 31601631 is about 5621.5327980899. The cubic root of 31601631 is about 316.1572649613.

The spelling of 31601631 in words is "thirty-one million, six hundred one thousand, six hundred thirty-one".