91157538991 has 8 divisors (see below), whose sum is σ = 92199430368. Its totient is φ = 90118380000.

The previous prime is 91157538949. The next prime is 91157539001. The reversal of 91157538991 is 19983575119.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 91157538991 - 2¹⁹ = 91157014703 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (91157538691) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 615955 + ... + 749476.

It is an arithmetic number, because the mean of its divisors is an integer number (11524928796).

Almost surely, 2^91157538991 is an apocalyptic number.

91157538991 is a deficient number, since it is larger than the sum of its proper divisors (1041891377).

91157538991 is a wasteful number, since it uses less digits than its factorization.

91157538991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1366193.

The product of its digits is 3061800, while the sum is 58.

The spelling of 91157538991 in words is "ninety-one billion, one hundred fifty-seven million, five hundred thirty-eight thousand, nine hundred ninety-one".