21713727689 has 4 divisors (see below), whose sum is σ = 22069690500. Its totient is φ = 21357764880.

The previous prime is 21713727661. The next prime is 21713727719. The reversal of 21713727689 is 98672731712.

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

It can be written as a sum of positive squares in 2 ways, for example, as 261145600 + 21452582089 = 16160^2 + 146467^2 .

It is a cyclic number.

It is not a de Polignac number, because 21713727689 - 2²⁰ = 21712679113 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21713727689.

It is not an unprimeable number, because it can be changed into a prime (21713727619) 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, 177981314 + ... + 177981435.

It is an arithmetic number, because the mean of its divisors is an integer number (5517422625).

Almost surely, 2^21713727689 is an apocalyptic number.

It is an amenable number.

21713727689 is a deficient number, since it is larger than the sum of its proper divisors (355962811).

21713727689 is an equidigital number, since it uses as much as digits as its factorization.

21713727689 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 355962810.

The product of its digits is 1778112, while the sum is 53.

The spelling of 21713727689 in words is "twenty-one billion, seven hundred thirteen million, seven hundred twenty-seven thousand, six hundred eighty-nine".