21722652397 has 4 divisors (see below), whose sum is σ = 21741331680. Its totient is φ = 21703973116.

The previous prime is 21722652361. The next prime is 21722652433. The reversal of 21722652397 is 79325622712.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is an interprime number because it is at equal distance from previous prime (21722652361) and next prime (21722652433).

It is a cyclic number.

It is not a de Polignac number, because 21722652397 - 2²³ = 21714263789 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21722652317) 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, 9337897 + ... + 9340222.

It is an arithmetic number, because the mean of its divisors is an integer number (5435332920).

Almost surely, 2^21722652397 is an apocalyptic number.

It is an amenable number.

21722652397 is a deficient number, since it is larger than the sum of its proper divisors (18679283).

21722652397 is a wasteful number, since it uses less digits than its factorization.

21722652397 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18679282.

The product of its digits is 635040, while the sum is 46.

The spelling of 21722652397 in words is "twenty-one billion, seven hundred twenty-two million, six hundred fifty-two thousand, three hundred ninety-seven".