998978695920 has 480 divisors, whose sum is σ = 3553515935424. Its totient is φ = 260726169600.

The previous prime is 998978695853. The next prime is 998978695921. The reversal of 998978695920 is 29596879899.

998978695920 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a Harshad number since it is a multiple of its sum of digits (81).

It is a self number, because there is not a number n which added to its sum of digits gives 998978695920.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (998978695921) by changing a digit.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 536795790 + ... + 536797650.

Almost surely, 2^998978695920 is an apocalyptic number.

998978695920 is a gapful number since it is divisible by the number (90) 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 998978695920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1776757967712).

998978695920 is an abundant number, since it is smaller than the sum of its proper divisors (2554537239504).

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

998978695920 is a wasteful number, since it uses less digits than its factorization.

998978695920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2463 (or 2445 counting only the distinct ones).

The product of its (nonzero) digits is 1587237120, while the sum is 81.

The spelling of 998978695920 in words is "nine hundred ninety-eight billion, nine hundred seventy-eight million, six hundred ninety-five thousand, nine hundred twenty".