21579023 has 2 divisors, whose sum is σ = 21579024. Its totient is φ = 21579022.

The previous prime is 21579017. The next prime is 21579031. The reversal of 21579023 is 32097512.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21579023 is a prime.

It is equal to p_1364249 and since 21579023 and 1364249 have the same sum of digits, it is a Honaker prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21579043) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10789511 + 10789512.

It is an arithmetic number, because the mean of its divisors is an integer number (10789512).

Almost surely, 2^21579023 is an apocalyptic number.

21579023 is a deficient number, since it is larger than the sum of its proper divisors (1).

21579023 is an equidigital number, since it uses as much as digits as its factorization.

21579023 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 3780, while the sum is 29.

The square root of 21579023 is about 4645.3227013847. The cubic root of 21579023 is about 278.4051465488.

The spelling of 21579023 in words is "twenty-one million, five hundred seventy-nine thousand, twenty-three".