21336780138 has 32 divisors (see below), whose sum is σ = 45273707136. Its totient is φ = 6680567808.

The previous prime is 21336780109. The next prime is 21336780163. The reversal of 21336780138 is 83108763312.

It is a self number, because there is not a number n which added to its sum of digits gives 21336780138.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 156631 + ... + 259242.

It is an arithmetic number, because the mean of its divisors is an integer number (1414803348).

Almost surely, 2^21336780138 is an apocalyptic number.

21336780138 is an abundant number, since it is smaller than the sum of its proper divisors (23936926998).

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

21336780138 is a wasteful number, since it uses less digits than its factorization.

21336780138 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 416398.

The product of its (nonzero) digits is 145152, while the sum is 42.

The spelling of 21336780138 in words is "twenty-one billion, three hundred thirty-six million, seven hundred eighty thousand, one hundred thirty-eight".