21213589 has 4 divisors (see below), whose sum is σ = 21247840. Its totient is φ = 21179340.

The previous prime is 21213583. The next prime is 21213611. The reversal of 21213589 is 98531212.

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 a cyclic number.

It is not a de Polignac number, because 21213589 - 2⁷ = 21213461 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21213589.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21213583) 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, 16179 + ... + 17440.

It is an arithmetic number, because the mean of its divisors is an integer number (5311960).

Almost surely, 2^21213589 is an apocalyptic number.

It is an amenable number.

21213589 is a deficient number, since it is larger than the sum of its proper divisors (34251).

21213589 is an equidigital number, since it uses as much as digits as its factorization.

21213589 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 34250.

The product of its digits is 4320, while the sum is 31.

The square root of 21213589 is about 4605.8212079932. The cubic root of 21213589 is about 276.8246227901.

The spelling of 21213589 in words is "twenty-one million, two hundred thirteen thousand, five hundred eighty-nine".