131951581 has 2 divisors, whose sum is σ = 131951582. Its totient is φ = 131951580.

The previous prime is 131951579. The next prime is 131951623. The reversal of 131951581 is 185159131.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 87516025 + 44435556 = 9355^2 + 6666^2 .

It is a cyclic number.

It is not a de Polignac number, because 131951581 - 2¹ = 131951579 is a prime.

It is a super-2 number, since 2×131951581² = 34822439456799122, which contains 22 as substring.

Together with 131951579, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (131951381) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 65975790 + 65975791.

It is an arithmetic number, because the mean of its divisors is an integer number (65975791).

Almost surely, 2^131951581 is an apocalyptic number.

It is an amenable number.

131951581 is a deficient number, since it is larger than the sum of its proper divisors (1).

131951581 is an equidigital number, since it uses as much as digits as its factorization.

131951581 is an evil number, because the sum of its binary digits is even.

The product of its digits is 5400, while the sum is 34.

The square root of 131951581 is about 11487.0179333019. The cubic root of 131951581 is about 509.1020737260.

It can be divided in two parts, 1319 and 51581, that added together give a square (52900 = 230²).

The spelling of 131951581 in words is "one hundred thirty-one million, nine hundred fifty-one thousand, five hundred eighty-one".