21722975 has 12 divisors (see below), whose sum is σ = 27307776. Its totient is φ = 17138880.

The previous prime is 21722963. The next prime is 21722983. The reversal of 21722975 is 57922712.

It is not a de Polignac number, because 21722975 - 2¹⁰ = 21721951 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 4127 + ... + 7776.

It is an arithmetic number, because the mean of its divisors is an integer number (2275648).

Almost surely, 2^21722975 is an apocalyptic number.

21722975 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

21722975 is a deficient number, since it is larger than the sum of its proper divisors (5584801).

21722975 is a wasteful number, since it uses less digits than its factorization.

21722975 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11986 (or 11981 counting only the distinct ones).

The product of its digits is 17640, while the sum is 35.

The square root of 21722975 is about 4660.7912418387. The cubic root of 21722975 is about 279.0228481265.

The spelling of 21722975 in words is "twenty-one million, seven hundred twenty-two thousand, nine hundred seventy-five".