20998400508 has 72 divisors (see below), whose sum is σ = 54119415168. Its totient is φ = 6862497408.

The previous prime is 20998400483. The next prime is 20998400519. The reversal of 20998400508 is 80500489902.

It is a congruent number.

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, 3475266 + ... + 3481302.

It is an arithmetic number, because the mean of its divisors is an integer number (751658544).

Almost surely, 2^20998400508 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 20998400508, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (27059707584).

20998400508 is an abundant number, since it is smaller than the sum of its proper divisors (33121014660).

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

20998400508 is a wasteful number, since it uses less digits than its factorization.

20998400508 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7923 (or 7918 counting only the distinct ones).

The product of its (nonzero) digits is 207360, while the sum is 45.

The spelling of 20998400508 in words is "twenty billion, nine hundred ninety-eight million, four hundred thousand, five hundred eight".