999910121 has 6 divisors (see below), whose sum is σ = 1163160810. Its totient is φ = 857065776.

The previous prime is 999910117. The next prime is 999910129. The reversal of 999910121 is 121019999.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 802928896 + 196981225 = 28336^2 + 14035^2 .

It is not a de Polignac number, because 999910121 - 2² = 999910117 is a prime.

It is not an unprimeable number, because it can be changed into a prime (999910129) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 10203116 + ... + 10203213.

It is an arithmetic number, because the mean of its divisors is an integer number (193860135).

Almost surely, 2^999910121 is an apocalyptic number.

It is an amenable number.

999910121 is a deficient number, since it is larger than the sum of its proper divisors (163250689).

999910121 is a wasteful number, since it uses less digits than its factorization.

999910121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20406343 (or 20406336 counting only the distinct ones).

The product of its (nonzero) digits is 13122, while the sum is 41.

The square root of 999910121 is about 31621.3554579812. The cubic root of 999910121 is about 999.9700394357.

The spelling of 999910121 in words is "nine hundred ninety-nine million, nine hundred ten thousand, one hundred twenty-one".