91819714921 has 4 divisors (see below), whose sum is σ = 100166961744. Its totient is φ = 83472468100.

The previous prime is 91819714913. The next prime is 91819714933. The reversal of 91819714921 is 12941791819.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 91819714921 - 2³ = 91819714913 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (91819714121) by changing a digit.

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 3 ways as a sum of consecutive naturals, for example, 4173623395 + ... + 4173623416.

It is an arithmetic number, because the mean of its divisors is an integer number (25041740436).

Almost surely, 2^91819714921 is an apocalyptic number.

It is an amenable number.

91819714921 is a deficient number, since it is larger than the sum of its proper divisors (8347246823).

91819714921 is a wasteful number, since it uses less digits than its factorization.

91819714921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8347246822.

The product of its digits is 326592, while the sum is 52.

The spelling of 91819714921 in words is "ninety-one billion, eight hundred nineteen million, seven hundred fourteen thousand, nine hundred twenty-one".