991135575793 has 4 divisors (see below), whose sum is σ = 1081238809968. Its totient is φ = 901032341620.

The previous prime is 991135575769. The next prime is 991135575799. The reversal of 991135575793 is 397575531199.

991135575793 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 991135575793 - 2²¹ = 991133478641 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (991135575799) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 45051617071 + ... + 45051617092.

It is an arithmetic number, because the mean of its divisors is an integer number (270309702492).

Almost surely, 2^991135575793 is an apocalyptic number.

It is an amenable number.

991135575793 is a deficient number, since it is larger than the sum of its proper divisors (90103234175).

991135575793 is a wasteful number, since it uses less digits than its factorization.

991135575793 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 90103234174.

The product of its digits is 40186125, while the sum is 64.

The spelling of 991135575793 in words is "nine hundred ninety-one billion, one hundred thirty-five million, five hundred seventy-five thousand, seven hundred ninety-three".