99090921 has 16 divisors (see below), whose sum is σ = 136040000. Its totient is φ = 64110528.

The previous prime is 99090869. The next prime is 99090967. The reversal of 99090921 is 12909099.

It is a happy number.

It is not a de Polignac number, because 99090921 - 2⁷ = 99090793 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 99090921.

It is not an unprimeable number, because it can be changed into a prime (99090221) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 54495 + ... + 56283.

It is an arithmetic number, because the mean of its divisors is an integer number (8502500).

Almost surely, 2^99090921 is an apocalyptic number.

It is an amenable number.

99090921 is a deficient number, since it is larger than the sum of its proper divisors (36949079).

99090921 is a wasteful number, since it uses less digits than its factorization.

99090921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2328.

The product of its (nonzero) digits is 13122, while the sum is 39.

The square root of 99090921 is about 9954.4422746832. The cubic root of 99090921 is about 462.7480759222.

The spelling of 99090921 in words is "ninety-nine million, ninety thousand, nine hundred twenty-one".