991909000 has 32 divisors (see below), whose sum is σ = 2321069400. Its totient is φ = 396763200.

The previous prime is 991908991. The next prime is 991909021. The reversal of 991909000 is 909199.

991909000 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 4 ways, for example, as 227828836 + 764080164 = 15094^2 + 27642^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 494955 + ... + 496954.

Almost surely, 2^991909000 is an apocalyptic number.

It is an amenable number.

991909000 is an abundant number, since it is smaller than the sum of its proper divisors (1329160400).

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

991909000 is a wasteful number, since it uses less digits than its factorization.

991909000 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 991930 (or 991916 counting only the distinct ones).

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

The square root of 991909000 is about 31494.5868364708. The cubic root of 991909000 is about 997.2956933178.

The spelling of 991909000 in words is "nine hundred ninety-one million, nine hundred nine thousand".