91623779215 has 4 divisors (see below), whose sum is σ = 109948535064. Its totient is φ = 73299023368.

The previous prime is 91623779113. The next prime is 91623779237. The reversal of 91623779215 is 51297732619.

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 91623779215 - 2¹⁵ = 91623746447 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 9162377917 + ... + 9162377926.

It is an arithmetic number, because the mean of its divisors is an integer number (27487133766).

Almost surely, 2^91623779215 is an apocalyptic number.

91623779215 is a deficient number, since it is larger than the sum of its proper divisors (18324755849).

91623779215 is a wasteful number, since it uses less digits than its factorization.

91623779215 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18324755848.

The product of its digits is 1428840, while the sum is 52.

The spelling of 91623779215 in words is "ninety-one billion, six hundred twenty-three million, seven hundred seventy-nine thousand, two hundred fifteen".