91561895730 has 24 divisors (see below), whose sum is σ = 238060929132. Its totient is φ = 24416505504.

The previous prime is 91561895651. The next prime is 91561895741. The reversal of 91561895730 is 3759816519.

91561895730 is a `hidden beast` number, since 9 + 1 + 5 + 61 + 8 + 9 + 573 + 0 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 86522457609 + 5039438121 = 294147^2 + 70989^2 .

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 508677109 + ... + 508677288.

Almost surely, 2^91561895730 is an apocalyptic number.

91561895730 is a gapful number since it is divisible by the number (90) formed by its first and last digit.

91561895730 is an abundant number, since it is smaller than the sum of its proper divisors (146499033402).

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

91561895730 is a wasteful number, since it uses less digits than its factorization.

91561895730 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1017354410 (or 1017354407 counting only the distinct ones).

The product of its (nonzero) digits is 2041200, while the sum is 54.

The spelling of 91561895730 in words is "ninety-one billion, five hundred sixty-one million, eight hundred ninety-five thousand, seven hundred thirty".