991900900 has 18 divisors (see below), whose sum is σ = 2152425170. Its totient is φ = 396760320.

The previous prime is 991900867. The next prime is 991900937. The reversal of 991900900 is 9009199.

It can be written as a sum of positive squares in 3 ways, for example, as 21827584 + 970073316 = 4672^2 + 31146^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 991900900.

It is an unprimeable number.

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 5 ways as a sum of consecutive naturals, for example, 4959405 + ... + 4959604.

Almost surely, 2^991900900 is an apocalyptic number.

It is an amenable number.

991900900 is an abundant number, since it is smaller than the sum of its proper divisors (1160524270).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

991900900 is a wasteful number, since it uses less digits than its factorization.

991900900 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9919023 (or 9919016 counting only the distinct ones).

The product of its (nonzero) digits is 6561, while the sum is 37.

The square root of 991900900 is about 31494.4582426814. The cubic root of 991900900 is about 997.2929786477.

The spelling of 991900900 in words is "nine hundred ninety-one million, nine hundred thousand, nine hundred".