20991815298 has 24 divisors (see below), whose sum is σ = 45544856448. Its totient is φ = 6987642552.

The previous prime is 20991815297. The next prime is 20991815303. The reversal of 20991815298 is 89251819902.

20991815298 is a `hidden beast` number, since 20 + 9 + 91 + 8 + 1 + 529 + 8 = 666.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (20991815297) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 788986 + ... + 815157.

It is an arithmetic number, because the mean of its divisors is an integer number (1897702352).

Almost surely, 2^20991815298 is an apocalyptic number.

20991815298 is an abundant number, since it is smaller than the sum of its proper divisors (24553041150).

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

20991815298 is a wasteful number, since it uses less digits than its factorization.

20991815298 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1604878 (or 1604875 counting only the distinct ones).

The product of its (nonzero) digits is 933120, while the sum is 54.

The spelling of 20991815298 in words is "twenty billion, nine hundred ninety-one million, eight hundred fifteen thousand, two hundred ninety-eight".