91939321855 has 4 divisors (see below), whose sum is σ = 110327186232. Its totient is φ = 73551457480.

The previous prime is 91939321849. The next prime is 91939321871. The reversal of 91939321855 is 55812393919.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 55812393919 = 3491 ⋅15987509.

It is not a de Polignac number, because 91939321855 - 2⁵ = 91939321823 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 91939321796 and 91939321805.

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, 9193932181 + ... + 9193932190.

It is an arithmetic number, because the mean of its divisors is an integer number (27581796558).

Almost surely, 2^91939321855 is an apocalyptic number.

91939321855 is a deficient number, since it is larger than the sum of its proper divisors (18387864377).

91939321855 is a wasteful number, since it uses less digits than its factorization.

91939321855 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18387864376.

The product of its digits is 2624400, while the sum is 55.

The spelling of 91939321855 in words is "ninety-one billion, nine hundred thirty-nine million, three hundred twenty-one thousand, eight hundred fifty-five".