991897716 has 12 divisors (see below), whose sum is σ = 2314428032. Its totient is φ = 330632568.

The previous prime is 991897667. The next prime is 991897723. The reversal of 991897716 is 617798199.

It is a tau number, because it is divible by the number of its divisors (12).

It is a super-2 number, since 2×991897716² = 1967722158012033312, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 41329060 + ... + 41329083.

Almost surely, 2^991897716 is an apocalyptic number.

It is an amenable number.

991897716 is an abundant number, since it is smaller than the sum of its proper divisors (1322530316).

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

991897716 is a wasteful number, since it uses less digits than its factorization.

991897716 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 82658150 (or 82658148 counting only the distinct ones).

The product of its digits is 1714608, while the sum is 57.

The square root of 991897716 is about 31494.4076940653. The cubic root of 991897716 is about 997.2919115437.

The spelling of 991897716 in words is "nine hundred ninety-one million, eight hundred ninety-seven thousand, seven hundred sixteen".