991401513984 has 220 divisors, whose sum is σ = 3383451975904. Its totient is φ = 283257409536.

The previous prime is 991401513959. The next prime is 991401513997. The reversal of 991401513984 is 489315104199.

It is a happy number.

991401513984 is a `hidden beast` number, since 9 + 9 + 1 + 40 + 1 + 513 + 9 + 84 = 666.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a self number, because there is not a number n which added to its sum of digits gives 991401513984.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 273154 + ... + 1434369.

Almost surely, 2^991401513984 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 991401513984, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1691725987952).

991401513984 is an abundant number, since it is smaller than the sum of its proper divisors (2392050461920).

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

991401513984 is a wasteful number, since it uses less digits than its factorization.

991401513984 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1707562 (or 1707535 counting only the distinct ones).

The product of its (nonzero) digits is 1399680, while the sum is 54.

The spelling of 991401513984 in words is "nine hundred ninety-one billion, four hundred one million, five hundred thirteen thousand, nine hundred eighty-four".