91007981568 has 480 divisors, whose sum is σ = 313105272480. Its totient is φ = 25798901760.

The previous prime is 91007981563. The next prime is 91007981579. The reversal of 91007981568 is 86518970019.

91007981568 is a `hidden beast` number, since 9 + 1 + 0 + 0 + 79 + 8 + 1 + 568 = 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 (91007981563) by changing a digit.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 210179880 + ... + 210180312.

It is an arithmetic number, because the mean of its divisors is an integer number (652302651).

Almost surely, 2^91007981568 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 91007981568, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (156552636240).

91007981568 is an abundant number, since it is smaller than the sum of its proper divisors (222097290912).

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

91007981568 is a wasteful number, since it uses less digits than its factorization.

91007981568 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 655 (or 626 counting only the distinct ones).

The product of its (nonzero) digits is 1088640, while the sum is 54.

The spelling of 91007981568 in words is "ninety-one billion, seven million, nine hundred eighty-one thousand, five hundred sixty-eight".