21468589 has 2 divisors, whose sum is σ = 21468590. Its totient is φ = 21468588.

The previous prime is 21468581. The next prime is 21468593. The reversal of 21468589 is 98586412.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 15539364 + 5929225 = 3942^2 + 2435^2 .

It is a cyclic number.

It is not a de Polignac number, because 21468589 - 2³ = 21468581 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21468581) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10734294 + 10734295.

It is an arithmetic number, because the mean of its divisors is an integer number (10734295).

Almost surely, 2^21468589 is an apocalyptic number.

It is an amenable number.

21468589 is a deficient number, since it is larger than the sum of its proper divisors (1).

21468589 is an equidigital number, since it uses as much as digits as its factorization.

21468589 is an evil number, because the sum of its binary digits is even.

The product of its digits is 138240, while the sum is 43.

The square root of 21468589 is about 4633.4208744728. The cubic root of 21468589 is about 277.9294068811.

The spelling of 21468589 in words is "twenty-one million, four hundred sixty-eight thousand, five hundred eighty-nine".