991131813485008 has 40 divisors (see below), whose sum is σ = 2068038466582536. Its totient is φ = 457444608000000.

The previous prime is 991131813484961. The next prime is 991131813485119. The reversal of 991131813485008 is 800584318131199.

It can be written as a sum of positive squares in 4 ways, for example, as 289475923776064 + 701655889708944 = 17013992^2 + 26488788^2 .

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 116532408 + ... + 124748008.

Almost surely, 2^{991131813485008} is an apocalyptic number.

It is an amenable number.

991131813485008 is an abundant number, since it is smaller than the sum of its proper divisors (1076906653097528).

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

991131813485008 is a wasteful number, since it uses less digits than its factorization.

991131813485008 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8795623 (or 8795617 counting only the distinct ones).

The product of its (nonzero) digits is 7464960, while the sum is 61.

The spelling of 991131813485008 in words is "nine hundred ninety-one trillion, one hundred thirty-one billion, eight hundred thirteen million, four hundred eighty-five thousand, eight".