21379956653 has 16 divisors (see below), whose sum is σ = 24926387904. Its totient is φ = 18122031360.

The previous prime is 21379956641. The next prime is 21379956733. The reversal of 21379956653 is 35665997312.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 21379956653 - 2²⁰ = 21378908077 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21379956553) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 514250 + ... + 554267.

It is an arithmetic number, because the mean of its divisors is an integer number (1557899244).

Almost surely, 2^21379956653 is an apocalyptic number.

It is an amenable number.

21379956653 is a deficient number, since it is larger than the sum of its proper divisors (3546431251).

21379956653 is a wasteful number, since it uses less digits than its factorization.

21379956653 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1068652.

The product of its digits is 9185400, while the sum is 56.

The spelling of 21379956653 in words is "twenty-one billion, three hundred seventy-nine million, nine hundred fifty-six thousand, six hundred fifty-three".