991814520 has 32 divisors (see below), whose sum is σ = 2975443920. Its totient is φ = 264483840.

The previous prime is 991814519. The next prime is 991814521. The reversal of 991814520 is 25418199.

It is an interprime number because it is at equal distance from previous prime (991814519) and next prime (991814521).

It is a Smith number, since the sum of its digits (39) coincides with the sum of the digits of its prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (991814521) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4132441 + ... + 4132680.

Almost surely, 2^991814520 is an apocalyptic number.

It is an amenable number.

991814520 is an abundant number, since it is smaller than the sum of its proper divisors (1983629400).

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

991814520 is a wasteful number, since it uses less digits than its factorization.

991814520 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8265135 (or 8265131 counting only the distinct ones).

The product of its (nonzero) digits is 25920, while the sum is 39.

The square root of 991814520 is about 31493.0868604524. The cubic root of 991814520 is about 997.2640279504.

The spelling of 991814520 in words is "nine hundred ninety-one million, eight hundred fourteen thousand, five hundred twenty".