991044909 has 16 divisors (see below), whose sum is σ = 1488896640. Its totient is φ = 651389760.

The previous prime is 991044893. The next prime is 991044911. The reversal of 991044909 is 909440199.

It is not a de Polignac number, because 991044909 - 2⁴ = 991044893 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (991044409) 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, 256572 + ... + 260405.

It is an arithmetic number, because the mean of its divisors is an integer number (93056040).

Almost surely, 2^991044909 is an apocalyptic number.

It is an amenable number.

991044909 is a deficient number, since it is larger than the sum of its proper divisors (497851731).

991044909 is a wasteful number, since it uses less digits than its factorization.

991044909 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 517057 (or 517051 counting only the distinct ones).

The product of its (nonzero) digits is 104976, while the sum is 45.

The square root of 991044909 is about 31480.8657600137. The cubic root of 991044909 is about 997.0060146645.

The spelling of 991044909 in words is "nine hundred ninety-one million, forty-four thousand, nine hundred nine".