91137785856 has 480 divisors, whose sum is σ = 279030140928. Its totient is φ = 26258964480.

The previous prime is 91137785839. The next prime is 91137785897. The reversal of 91137785856 is 65858773119.

It is a happy number.

It is a super-2 number, since 2×91137785856² (a number of 23 digits) contains 22 as substring.

Its product of digits (12700800) is a multiple of the sum of its prime factors (225).

It is a self number, because there is not a number n which added to its sum of digits gives 91137785856.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 851754955 + ... + 851755061.

Almost surely, 2^91137785856 is an apocalyptic number.

91137785856 is a gapful number since it is divisible by the number (96) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 91137785856, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (139515070464).

91137785856 is an abundant number, since it is smaller than the sum of its proper divisors (187892355072).

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

91137785856 is a wasteful number, since it uses less digits than its factorization.

91137785856 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 225 (or 199 counting only the distinct ones).

The product of its digits is 12700800, while the sum is 60.

The spelling of 91137785856 in words is "ninety-one billion, one hundred thirty-seven million, seven hundred eighty-five thousand, eight hundred fifty-six".