991512567932544 has 768 divisors, whose sum is σ = 3328163492659200. Its totient is φ = 277507051315200.

The previous prime is 991512567932519. The next prime is 991512567932581. The reversal of 991512567932544 is 445239765215199.

991512567932544 is a `hidden beast` number, since 9 + 9 + 1 + 5 + 1 + 2 + 5 + 6 + 79 + 3 + 2 + 544 = 666.

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

It is an unprimeable number.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 37961339517 + ... + 37961365635.

It is an arithmetic number, because the mean of its divisors is an integer number (4333546214400).

Almost surely, 2^{991512567932544} 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 991512567932544, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1664081746329600).

991512567932544 is an abundant number, since it is smaller than the sum of its proper divisors (2336650924726656).

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

991512567932544 is a wasteful number, since it uses less digits than its factorization.

991512567932544 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 26741 (or 26726 counting only the distinct ones).

The product of its digits is 734832000, while the sum is 72.

The spelling of 991512567932544 in words is "nine hundred ninety-one trillion, five hundred twelve billion, five hundred sixty-seven million, nine hundred thirty-two thousand, five hundred forty-four".