21286838780 has 24 divisors (see below), whose sum is σ = 45144963360. Its totient is φ = 8430430400.

The previous prime is 21286838719. The next prime is 21286838819. The reversal of 21286838780 is 8783868212.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 5267000 + ... + 5271039.

It is an arithmetic number, because the mean of its divisors is an integer number (1881040140).

Almost surely, 2^21286838780 is an apocalyptic number.

21286838780 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21286838780 is an abundant number, since it is smaller than the sum of its proper divisors (23858124580).

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

21286838780 is a wasteful number, since it uses less digits than its factorization.

21286838780 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10538149 (or 10538147 counting only the distinct ones).

The product of its (nonzero) digits is 2064384, while the sum is 53.

The spelling of 21286838780 in words is "twenty-one billion, two hundred eighty-six million, eight hundred thirty-eight thousand, seven hundred eighty".