21722723639 has 4 divisors (see below), whose sum is σ = 21723026424. Its totient is φ = 21722420856.

The previous prime is 21722723591. The next prime is 21722723653. The reversal of 21722723639 is 93632722712.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 21722723639 - 2¹⁶ = 21722658103 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 21722723639.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21722723669) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 23804 + ... + 209790.

It is an arithmetic number, because the mean of its divisors is an integer number (5430756606).

Almost surely, 2^21722723639 is an apocalyptic number.

21722723639 is a deficient number, since it is larger than the sum of its proper divisors (302785).

21722723639 is a wasteful number, since it uses less digits than its factorization.

21722723639 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 302784.

The product of its digits is 381024, while the sum is 44.

The spelling of 21722723639 in words is "twenty-one billion, seven hundred twenty-two million, seven hundred twenty-three thousand, six hundred thirty-nine".