991306972755 has 32 divisors (see below), whose sum is σ = 1922534737920. Its totient is φ = 480633683040.

The previous prime is 991306972741. The next prime is 991306972759. The reversal of 991306972755 is 557279603199.

It is not a de Polignac number, because 991306972755 - 2²⁵ = 991273418323 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 991306972692 and 991306972701.

It is not an unprimeable number, because it can be changed into a prime (991306972759) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 333771907 + ... + 333774876.

It is an arithmetic number, because the mean of its divisors is an integer number (60079210560).

Almost surely, 2^991306972755 is an apocalyptic number.

991306972755 is a deficient number, since it is larger than the sum of its proper divisors (931227765165).

991306972755 is a wasteful number, since it uses less digits than its factorization.

991306972755 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 667546808 (or 667546802 counting only the distinct ones).

The product of its (nonzero) digits is 32148900, while the sum is 63.

The spelling of 991306972755 in words is "nine hundred ninety-one billion, three hundred six million, nine hundred seventy-two thousand, seven hundred fifty-five".