21722679 has 24 divisors (see below), whose sum is σ = 34819200. Its totient is φ = 12938640.

The previous prime is 21722671. The next prime is 21722689. The reversal of 21722679 is 97622712.

It is not a de Polignac number, because 21722679 - 2³ = 21722671 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21722671) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 3982 + ... + 7700.

It is an arithmetic number, because the mean of its divisors is an integer number (1450800).

Almost surely, 2^21722679 is an apocalyptic number.

21722679 is a deficient number, since it is larger than the sum of its proper divisors (13096521).

21722679 is a wasteful number, since it uses less digits than its factorization.

21722679 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3795 (or 3792 counting only the distinct ones).

The product of its digits is 21168, while the sum is 36.

The square root of 21722679 is about 4660.7594874655. The cubic root of 21722679 is about 279.0215807872.

It can be divided in two parts, 2172 and 2679, that added together give a triangular number (4851 = T₉₈).

The spelling of 21722679 in words is "twenty-one million, seven hundred twenty-two thousand, six hundred seventy-nine".