21039589 has 2 divisors, whose sum is σ = 21039590. Its totient is φ = 21039588.

The previous prime is 21039581. The next prime is 21039611. The reversal of 21039589 is 98593012.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 17994564 + 3045025 = 4242^2 + 1745^2 .

It is a cyclic number.

It is not a de Polignac number, because 21039589 - 2³ = 21039581 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21039581) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10519794 + 10519795.

It is an arithmetic number, because the mean of its divisors is an integer number (10519795).

Almost surely, 2^21039589 is an apocalyptic number.

It is an amenable number.

21039589 is a deficient number, since it is larger than the sum of its proper divisors (1).

21039589 is an equidigital number, since it uses as much as digits as its factorization.

21039589 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 19440, while the sum is 37.

The square root of 21039589 is about 4586.8931751241. The cubic root of 21039589 is about 276.0656787264.

The spelling of 21039589 in words is "twenty-one million, thirty-nine thousand, five hundred eighty-nine".