99792977921 has 32 divisors (see below), whose sum is σ = 128213729280. Its totient is φ = 75493813824.

The previous prime is 99792977917. The next prime is 99792977923. The reversal of 99792977921 is 12977929799.

It is not a de Polignac number, because 99792977921 - 2² = 99792977917 is a prime.

It is not an unprimeable number, because it can be changed into a prime (99792977923) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 6143216 + ... + 6159438.

It is an arithmetic number, because the mean of its divisors is an integer number (4006679040).

It is a Proth number, since it is equal to 47585 ⋅ 2²¹ + 1 and 47585 < 2²¹.

Almost surely, 2^99792977921 is an apocalyptic number.

99792977921 is a gapful number since it is divisible by the number (91) formed by its first and last digit.

It is an amenable number.

99792977921 is a deficient number, since it is larger than the sum of its proper divisors (28420751359).

99792977921 is a wasteful number, since it uses less digits than its factorization.

99792977921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19205.

The product of its digits is 81015228, while the sum is 71.

The spelling of 99792977921 in words is "ninety-nine billion, seven hundred ninety-two million, nine hundred seventy-seven thousand, nine hundred twenty-one".