21722613 has 8 divisors (see below), whose sum is σ = 31596576. Its totient is φ = 13165200.

The previous prime is 21722609. The next prime is 21722627. The reversal of 21722613 is 31622712.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21722613 - 2² = 21722609 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21722693) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 329098 + ... + 329163.

It is an arithmetic number, because the mean of its divisors is an integer number (3949572).

Almost surely, 2^21722613 is an apocalyptic number.

It is an amenable number.

21722613 is a deficient number, since it is larger than the sum of its proper divisors (9873963).

21722613 is a wasteful number, since it uses less digits than its factorization.

21722613 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 658275.

The product of its digits is 1008, while the sum is 24.

The square root of 21722613 is about 4660.7524070691. The cubic root of 21722613 is about 279.0212982032.

Subtracting 21722613 from its reverse (31622712), we obtain a palindrome (9900099).

The spelling of 21722613 in words is "twenty-one million, seven hundred twenty-two thousand, six hundred thirteen".