99180921 has 16 divisors (see below), whose sum is σ = 151280000. Its totient is φ = 56619648.

The previous prime is 99180911. The next prime is 99180929. The reversal of 99180921 is 12908199.

It is a happy number.

It is not a de Polignac number, because 99180921 - 2⁹ = 99180409 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 99180921.

It is not an unprimeable number, because it can be changed into a prime (99180929) 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, 31005 + ... + 34053.

It is an arithmetic number, because the mean of its divisors is an integer number (9455000).

Almost surely, 2^99180921 is an apocalyptic number.

It is an amenable number.

99180921 is a deficient number, since it is larger than the sum of its proper divisors (52099079).

99180921 is a wasteful number, since it uses less digits than its factorization.

99180921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4608.

The product of its (nonzero) digits is 11664, while the sum is 39.

The square root of 99180921 is about 9958.9618434855. The cubic root of 99180921 is about 462.8881315531. Note that the first 3 decimals are identical.

The spelling of 99180921 in words is "ninety-nine million, one hundred eighty thousand, nine hundred twenty-one".