21021589 has 4 divisors (see below), whose sum is σ = 21067456. Its totient is φ = 20975724.

The previous prime is 21021577. The next prime is 21021601. The reversal of 21021589 is 98512012.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is an interprime number because it is at equal distance from previous prime (21021577) and next prime (21021601).

It is a cyclic number.

It is not a de Polignac number, because 21021589 - 2¹¹ = 21019541 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21021529) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 22239 + ... + 23164.

It is an arithmetic number, because the mean of its divisors is an integer number (5266864).

Almost surely, 2^21021589 is an apocalyptic number.

It is an amenable number.

21021589 is a deficient number, since it is larger than the sum of its proper divisors (45867).

21021589 is an equidigital number, since it uses as much as digits as its factorization.

21021589 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 45866.

The product of its (nonzero) digits is 1440, while the sum is 28.

The square root of 21021589 is about 4584.9306428778. The cubic root of 21021589 is about 275.9869287725.

The spelling of 21021589 in words is "twenty-one million, twenty-one thousand, five hundred eighty-nine".