131581631 has 4 divisors (see below), whose sum is σ = 138507000. Its totient is φ = 124656264.

The previous prime is 131581627. The next prime is 131581633. The reversal of 131581631 is 136185131.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 136185131 = 29 ⋅4696039.

It is not a de Polignac number, because 131581631 - 2² = 131581627 is a prime.

It is a super-2 number, since 2×131581631² = 34627451233240322, 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 = 131581594 and 131581603.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (131581633) 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, 3462656 + ... + 3462693.

It is an arithmetic number, because the mean of its divisors is an integer number (34626750).

Almost surely, 2^131581631 is an apocalyptic number.

131581631 is a deficient number, since it is larger than the sum of its proper divisors (6925369).

131581631 is an equidigital number, since it uses as much as digits as its factorization.

131581631 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6925368.

The product of its digits is 2160, while the sum is 29.

The square root of 131581631 is about 11470.9036697202. The cubic root of 131581631 is about 508.6258419583.

The spelling of 131581631 in words is "one hundred thirty-one million, five hundred eighty-one thousand, six hundred thirty-one".