21641838979 has 4 divisors (see below), whose sum is σ = 22226753584. Its totient is φ = 21056924376.

The previous prime is 21641838913. The next prime is 21641838989. The reversal of 21641838979 is 97983814612.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21641838979 - 2⁷ = 21641838851 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21641838989) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 292457247 + ... + 292457320.

It is an arithmetic number, because the mean of its divisors is an integer number (5556688396).

Almost surely, 2^21641838979 is an apocalyptic number.

21641838979 is a deficient number, since it is larger than the sum of its proper divisors (584914605).

21641838979 is an equidigital number, since it uses as much as digits as its factorization.

21641838979 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 584914604.

The product of its digits is 5225472, while the sum is 58.

The spelling of 21641838979 in words is "twenty-one billion, six hundred forty-one million, eight hundred thirty-eight thousand, nine hundred seventy-nine".