21723238799 has 4 divisors (see below), whose sum is σ = 21725479080. Its totient is φ = 21720998520.

The previous prime is 21723238781. The next prime is 21723238807. The reversal of 21723238799 is 99783232712.

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 21723238799 - 2⁸ = 21723238543 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 21723238799.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21723238729) 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, 1105532 + ... + 1125009.

It is an arithmetic number, because the mean of its divisors is an integer number (5431369770).

Almost surely, 2^21723238799 is an apocalyptic number.

21723238799 is a deficient number, since it is larger than the sum of its proper divisors (2240281).

21723238799 is an equidigital number, since it uses as much as digits as its factorization.

21723238799 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2240280.

The product of its digits is 2286144, while the sum is 53.

The spelling of 21723238799 in words is "twenty-one billion, seven hundred twenty-three million, two hundred thirty-eight thousand, seven hundred ninety-nine".