899121999 has 16 divisors (see below), whose sum is σ = 1208908800. Its totient is φ = 594396000.

The previous prime is 899121961. The next prime is 899122019. The reversal of 899121999 is 999121998.

It is not a de Polignac number, because 899121999 - 2⁷ = 899121871 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (899121499) 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 15 ways as a sum of consecutive naturals, for example, 186874 + ... + 191624.

It is an arithmetic number, because the mean of its divisors is an integer number (75556800).

Almost surely, 2^899121999 is an apocalyptic number.

899121999 is a deficient number, since it is larger than the sum of its proper divisors (309786801).

899121999 is a wasteful number, since it uses less digits than its factorization.

899121999 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5270.

The product of its digits is 944784, while the sum is 57.

The square root of 899121999 is about 29985.3630793426. The cubic root of 899121999 is about 965.1753192520.

Subtracting 899121999 from its reverse (999121998), we obtain a palindrome (99999999).

The spelling of 899121999 in words is "eight hundred ninety-nine million, one hundred twenty-one thousand, nine hundred ninety-nine".