131957561 has 2 divisors, whose sum is σ = 131957562. Its totient is φ = 131957560.

The previous prime is 131957533. The next prime is 131957563. The reversal of 131957561 is 165759131.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 87067561 + 44890000 = 9331^2 + 6700^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-131957561 is a prime.

It is a super-3 number, since 3×131957561³ (a number of 25 digits) contains 333 as substring.

Together with 131957563, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (131957563) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 65978780 + 65978781.

It is an arithmetic number, because the mean of its divisors is an integer number (65978781).

Almost surely, 2^131957561 is an apocalyptic number.

It is an amenable number.

131957561 is a deficient number, since it is larger than the sum of its proper divisors (1).

131957561 is an equidigital number, since it uses as much as digits as its factorization.

131957561 is an evil number, because the sum of its binary digits is even.

The product of its digits is 28350, while the sum is 38.

The square root of 131957561 is about 11487.2782241922. The cubic root of 131957561 is about 509.1097643865.

The spelling of 131957561 in words is "one hundred thirty-one million, nine hundred fifty-seven thousand, five hundred sixty-one".