991297920059 has 4 divisors (see below), whose sum is σ = 991300016880. Its totient is φ = 991295823240.

The previous prime is 991297920047. The next prime is 991297920061. The reversal of 991297920059 is 950029792199.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 950029792199 = 31 ⋅30646122329.

It is a cyclic number.

It is not a de Polignac number, because 991297920059 - 2³⁶ = 922578443323 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 991297919983 and 991297920010.

It is not an unprimeable number, because it can be changed into a prime (991297950059) 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, 31562 + ... + 1408400.

It is an arithmetic number, because the mean of its divisors is an integer number (247825004220).

Almost surely, 2^991297920059 is an apocalyptic number.

991297920059 is a deficient number, since it is larger than the sum of its proper divisors (2096821).

991297920059 is a wasteful number, since it uses less digits than its factorization.

991297920059 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2096820.

The product of its (nonzero) digits is 8266860, while the sum is 62.

The spelling of 991297920059 in words is "nine hundred ninety-one billion, two hundred ninety-seven million, nine hundred twenty thousand, fifty-nine".