91581131 has 2 divisors, whose sum is σ = 91581132. Its totient is φ = 91581130.

The previous prime is 91581067. The next prime is 91581143. The reversal of 91581131 is 13118519.

It is a strong prime.

It is an emirp because it is prime and its reverse (13118519) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 91581131 - 2⁶ = 91581067 is a prime.

It is a super-2 number, since 2×91581131² = 16774207110478322, which contains 22 as substring.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 91581094 and 91581103.

It is not a weakly prime, because it can be changed into another prime (91581731) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 45790565 + 45790566.

It is an arithmetic number, because the mean of its divisors is an integer number (45790566).

Almost surely, 2^91581131 is an apocalyptic number.

91581131 is a deficient number, since it is larger than the sum of its proper divisors (1).

91581131 is an equidigital number, since it uses as much as digits as its factorization.

91581131 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1080, while the sum is 29.

The square root of 91581131 is about 9569.8030805237. The cubic root of 91581131 is about 450.7495836161.

The spelling of 91581131 in words is "ninety-one million, five hundred eighty-one thousand, one hundred thirty-one".