21224579 has 2 divisors, whose sum is σ = 21224580. Its totient is φ = 21224578.

The previous prime is 21224563. The next prime is 21224591. The reversal of 21224579 is 97542212.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21224579 - 2⁴ = 21224563 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (21224509) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10612289 + 10612290.

It is an arithmetic number, because the mean of its divisors is an integer number (10612290).

Almost surely, 2^21224579 is an apocalyptic number.

21224579 is a deficient number, since it is larger than the sum of its proper divisors (1).

21224579 is an equidigital number, since it uses as much as digits as its factorization.

21224579 is an evil number, because the sum of its binary digits is even.

The product of its digits is 10080, while the sum is 32.

The square root of 21224579 is about 4607.0141089430. The cubic root of 21224579 is about 276.8724188418.

The spelling of 21224579 in words is "twenty-one million, two hundred twenty-four thousand, five hundred seventy-nine".