21722530 has 8 divisors (see below), whose sum is σ = 39100572. Its totient is φ = 8689008.

The previous prime is 21722509. The next prime is 21722531. The reversal of 21722530 is 3522712.

It can be written as a sum of positive squares in 2 ways, for example, as 20638849 + 1083681 = 4543^2 + 1041^2 .

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

It is not an unprimeable number, because it can be changed into a prime (21722531) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1086117 + ... + 1086136.

Almost surely, 2^21722530 is an apocalyptic number.

21722530 is a deficient number, since it is larger than the sum of its proper divisors (17378042).

21722530 is a wasteful number, since it uses less digits than its factorization.

21722530 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2172260.

The product of its (nonzero) digits is 840, while the sum is 22.

The square root of 21722530 is about 4660.7435029188. The cubic root of 21722530 is about 279.0209428317.

The spelling of 21722530 in words is "twenty-one million, seven hundred twenty-two thousand, five hundred thirty".