91664567999 has 4 divisors (see below), whose sum is σ = 91809837360. Its totient is φ = 91519298640.

The previous prime is 91664567989. The next prime is 91664568001. The reversal of 91664567999 is 99976546619.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 91664567999 - 2⁴ = 91664567983 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (91664567909) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 72633734 + ... + 72634995.

It is an arithmetic number, because the mean of its divisors is an integer number (22952459340).

Almost surely, 2^91664567999 is an apocalyptic number.

91664567999 is a deficient number, since it is larger than the sum of its proper divisors (145269361).

91664567999 is a wasteful number, since it uses less digits than its factorization.

91664567999 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 145269360.

The product of its digits is 198404640, while the sum is 71.

The spelling of 91664567999 in words is "ninety-one billion, six hundred sixty-four million, five hundred sixty-seven thousand, nine hundred ninety-nine".