91509481566 has 160 divisors (see below), whose sum is σ = 211199788800. Its totient is φ = 29606497920.

The previous prime is 91509481537. The next prime is 91509481589. The reversal of 91509481566 is 66518490519.

91509481566 is a `hidden beast` number, since 9 + 1 + 509 + 4 + 81 + 56 + 6 = 666.

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

It is a congruent number.

It is an unprimeable number.

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 in 79 ways as a sum of consecutive naturals, for example, 294242551 + ... + 294242861.

It is an arithmetic number, because the mean of its divisors is an integer number (1319998680).

Almost surely, 2^91509481566 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 91509481566, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (105599894400).

91509481566 is an abundant number, since it is smaller than the sum of its proper divisors (119690307234).

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

91509481566 is a wasteful number, since it uses less digits than its factorization.

91509481566 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 716 (or 707 counting only the distinct ones).

The product of its (nonzero) digits is 2332800, while the sum is 54.

The spelling of 91509481566 in words is "ninety-one billion, five hundred nine million, four hundred eighty-one thousand, five hundred sixty-six".