131990981 has 2 divisors, whose sum is σ = 131990982. Its totient is φ = 131990980.

The previous prime is 131990959. The next prime is 131990983. The reversal of 131990981 is 189099131.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 118048225 + 13942756 = 10865^2 + 3734^2 .

It is a cyclic number.

It is not a de Polignac number, because 131990981 - 2²⁶ = 64882117 is a prime.

It is a super-2 number, since 2×131990981² = 34843238130684722, which contains 22 as substring.

Together with 131990983, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (131990983) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 65995490 + 65995491.

It is an arithmetic number, because the mean of its divisors is an integer number (65995491).

Almost surely, 2^131990981 is an apocalyptic number.

It is an amenable number.

131990981 is a deficient number, since it is larger than the sum of its proper divisors (1).

131990981 is an equidigital number, since it uses as much as digits as its factorization.

131990981 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 17496, while the sum is 41.

The square root of 131990981 is about 11488.7327847766. The cubic root of 131990981 is about 509.1527403555.

The spelling of 131990981 in words is "one hundred thirty-one million, nine hundred ninety thousand, nine hundred eighty-one".