91157538691 has 2 divisors, whose sum is σ = 91157538692. Its totient is φ = 91157538690.

The previous prime is 91157538613. The next prime is 91157538701. The reversal of 91157538691 is 19683575119.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 91157538691 - 2²¹ = 91155441539 is a prime.

It is not a weakly prime, because it can be changed into another prime (91157538611) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 45578769345 + 45578769346.

It is an arithmetic number, because the mean of its divisors is an integer number (45578769346).

Almost surely, 2^91157538691 is an apocalyptic number.

91157538691 is a deficient number, since it is larger than the sum of its proper divisors (1).

91157538691 is an equidigital number, since it uses as much as digits as its factorization.

91157538691 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2041200, while the sum is 55.

The spelling of 91157538691 in words is "ninety-one billion, one hundred fifty-seven million, five hundred thirty-eight thousand, six hundred ninety-one".