991617909275 has 12 divisors (see below), whose sum is σ = 1405264237392. Its totient is φ = 679966566240.

The previous prime is 991617909259. The next prime is 991617909371. The reversal of 991617909275 is 572909716199.

It is not a de Polignac number, because 991617909275 - 2⁴ = 991617909259 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 2833193852 + ... + 2833194201.

It is an arithmetic number, because the mean of its divisors is an integer number (117105353116).

Almost surely, 2^991617909275 is an apocalyptic number.

991617909275 is a deficient number, since it is larger than the sum of its proper divisors (413646328117).

991617909275 is a wasteful number, since it uses less digits than its factorization.

991617909275 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5666388070 (or 5666388065 counting only the distinct ones).

The product of its (nonzero) digits is 19289340, while the sum is 65.

The spelling of 991617909275 in words is "nine hundred ninety-one billion, six hundred seventeen million, nine hundred nine thousand, two hundred seventy-five".