131931981 has 12 divisors (see below), whose sum is σ = 190693152. Its totient is φ = 87897096.

The previous prime is 131931971. The next prime is 131931983. The reversal of 131931981 is 189139131.

It is not a de Polignac number, because 131931981 - 2⁵ = 131931949 is a prime.

It is a super-2 number, since 2×131931981² = 34812095221168722, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (131931983) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 13320 + ... + 21006.

It is an arithmetic number, because the mean of its divisors is an integer number (15891096).

Almost surely, 2^131931981 is an apocalyptic number.

It is an amenable number.

131931981 is a deficient number, since it is larger than the sum of its proper divisors (58761171).

131931981 is a wasteful number, since it uses less digits than its factorization.

131931981 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9600 (or 9597 counting only the distinct ones).

The product of its digits is 5832, while the sum is 36.

The square root of 131931981 is about 11486.1647646201. The cubic root of 131931981 is about 509.0768652502.

The spelling of 131931981 in words is "one hundred thirty-one million, nine hundred thirty-one thousand, nine hundred eighty-one".