91156591944 has 432 divisors, whose sum is σ = 291507740160. Its totient is φ = 26674401600.

The previous prime is 91156591943. The next prime is 91156591991. The reversal of 91156591944 is 44919565119.

91156591944 is a `hidden beast` number, since 9 + 1 + 1 + 5 + 6 + 591 + 9 + 44 = 666.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (91156591943) by changing a digit.

It is a polite number, since it can be written in 107 ways as a sum of consecutive naturals, for example, 196882257 + ... + 196882719.

Almost surely, 2^91156591944 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 91156591944, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (145753870080).

91156591944 is an abundant number, since it is smaller than the sum of its proper divisors (200351148216).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

91156591944 is a wasteful number, since it uses less digits than its factorization.

91156591944 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 546 (or 510 counting only the distinct ones).

The product of its digits is 1749600, while the sum is 54.

The spelling of 91156591944 in words is "ninety-one billion, one hundred fifty-six million, five hundred ninety-one thousand, nine hundred forty-four".