21726518771 has 4 divisors (see below), whose sum is σ = 21733666344. Its totient is φ = 21719371200.

The previous prime is 21726518767. The next prime is 21726518783. The reversal of 21726518771 is 17781562712.

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 21726518771 - 2² = 21726518767 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21726218771) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3569225 + ... + 3575306.

It is an arithmetic number, because the mean of its divisors is an integer number (5433416586).

Almost surely, 2^21726518771 is an apocalyptic number.

21726518771 is a deficient number, since it is larger than the sum of its proper divisors (7147573).

21726518771 is an equidigital number, since it uses as much as digits as its factorization.

21726518771 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7147572.

The product of its digits is 329280, while the sum is 47.

The spelling of 21726518771 in words is "twenty-one billion, seven hundred twenty-six million, five hundred eighteen thousand, seven hundred seventy-one".