21382116765 has 16 divisors (see below), whose sum is σ = 34461108288. Its totient is φ = 11320555136.

The previous prime is 21382116737. The next prime is 21382116779. The reversal of 21382116765 is 56761128312.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 21382116765 - 2⁵ = 21382116733 is a prime.

It is a Smith number, since the sum of its digits (42) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Curzon number.

It is a congruent number.

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, 5200407 + ... + 5204516.

It is an arithmetic number, because the mean of its divisors is an integer number (2153819268).

Almost surely, 2^21382116765 is an apocalyptic number.

It is an amenable number.

21382116765 is a deficient number, since it is larger than the sum of its proper divisors (13078991523).

21382116765 is a wasteful number, since it uses less digits than its factorization.

21382116765 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10405068.

The product of its digits is 120960, while the sum is 42.

The spelling of 21382116765 in words is "twenty-one billion, three hundred eighty-two million, one hundred sixteen thousand, seven hundred sixty-five".