131235581 has 2 divisors, whose sum is σ = 131235582. Its totient is φ = 131235580.

The previous prime is 131235569. The next prime is 131235589. The reversal of 131235581 is 185532131.

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., 101707225 + 29528356 = 10085^2 + 5434^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-131235581 is a prime.

It is a super-2 number, since 2×131235581² = 34445555440815122, which contains 22 as substring.

It is a Chen prime.

It is equal to p_7444316 and since 131235581 and 7444316 have the same sum of digits, it is a Honaker prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (131235589) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 65617790 + 65617791.

It is an arithmetic number, because the mean of its divisors is an integer number (65617791).

Almost surely, 2^131235581 is an apocalyptic number.

It is an amenable number.

131235581 is a deficient number, since it is larger than the sum of its proper divisors (1).

131235581 is an equidigital number, since it uses as much as digits as its factorization.

131235581 is an evil number, because the sum of its binary digits is even.

The product of its digits is 3600, while the sum is 29.

The square root of 131235581 is about 11455.8099233533. The cubic root of 131235581 is about 508.1795676699.

The spelling of 131235581 in words is "one hundred thirty-one million, two hundred thirty-five thousand, five hundred eighty-one".