21713579 has 2 divisors, whose sum is σ = 21713580. Its totient is φ = 21713578.

The previous prime is 21713567. The next prime is 21713603. The reversal of 21713579 is 97531712.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21713579 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (21713509) 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 as a sum of consecutive naturals, namely, 10856789 + 10856790.

It is an arithmetic number, because the mean of its divisors is an integer number (10856790).

Almost surely, 2^21713579 is an apocalyptic number.

21713579 is a deficient number, since it is larger than the sum of its proper divisors (1).

21713579 is an equidigital number, since it uses as much as digits as its factorization.

21713579 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 13230, while the sum is 35.

The square root of 21713579 is about 4659.7831494609. The cubic root of 21713579 is about 278.9826130487.

The spelling of 21713579 in words is "twenty-one million, seven hundred thirteen thousand, five hundred seventy-nine".