991957595136 has 88 divisors (see below), whose sum is σ = 2644389667584. Its totient is φ = 330594877440.

The previous prime is 991957595129. The next prime is 991957595137. The reversal of 991957595136 is 631595759199.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (991957595137) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 19884721 + ... + 19934543.

Almost surely, 2^991957595136 is an apocalyptic number.

991957595136 is a gapful number since it is divisible by the number (96) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 991957595136, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1322194833792).

991957595136 is an abundant number, since it is smaller than the sum of its proper divisors (1652432072448).

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

991957595136 is a wasteful number, since it uses less digits than its factorization.

991957595136 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 56327 (or 56309 counting only the distinct ones).

The product of its digits is 103335750, while the sum is 69.

The spelling of 991957595136 in words is "nine hundred ninety-one billion, nine hundred fifty-seven million, five hundred ninety-five thousand, one hundred thirty-six".