91981097999 has 16 divisors (see below), whose sum is σ = 112529452800. Its totient is φ = 73425455424.

The previous prime is 91981097959. The next prime is 91981098047. The reversal of 91981097999 is 99979018919.

It is a cyclic number.

It is not a de Polignac number, because 91981097999 - 2⁸ = 91981097743 is a prime.

It is a super-3 number, since 3×91981097999³ (a number of 34 digits) contains 333 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (91981097909) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 5853062 + ... + 5868755.

It is an arithmetic number, because the mean of its divisors is an integer number (7033090800).

Almost surely, 2^91981097999 is an apocalyptic number.

91981097999 is a deficient number, since it is larger than the sum of its proper divisors (20548354801).

91981097999 is a wasteful number, since it uses less digits than its factorization.

91981097999 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11721902.

The product of its (nonzero) digits is 29760696, while the sum is 71.

The spelling of 91981097999 in words is "ninety-one billion, nine hundred eighty-one million, ninety-seven thousand, nine hundred ninety-nine".