991567598256 has 120 divisors (see below), whose sum is σ = 2797331403776. Its totient is φ = 327874677120.

The previous prime is 991567598201. The next prime is 991567598279. The reversal of 991567598256 is 652895765199.

991567598256 is a `hidden beast` number, since 9 + 9 + 1 + 5 + 6 + 7 + 598 + 25 + 6 = 666.

It is a super-2 number, since 2×991567598256² (a number of 25 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (72).

It is an unprimeable number.

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 23 ways as a sum of consecutive naturals, for example, 9033141 + ... + 9142251.

Almost surely, 2^991567598256 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 991567598256, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1398665701888).

991567598256 is an abundant number, since it is smaller than the sum of its proper divisors (1805763805520).

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

991567598256 is a wasteful number, since it uses less digits than its factorization.

991567598256 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 109631 (or 109622 counting only the distinct ones).

The product of its digits is 367416000, while the sum is 72.

The spelling of 991567598256 in words is "nine hundred ninety-one billion, five hundred sixty-seven million, five hundred ninety-eight thousand, two hundred fifty-six".