21840589 has 4 divisors (see below), whose sum is σ = 21853980. Its totient is φ = 21827200.

The previous prime is 21840583. The next prime is 21840607. The reversal of 21840589 is 98504812.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 3204100 + 18636489 = 1790^2 + 4317^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21840589 is a prime.

It is a super-2 number, since 2×21840589² = 954022655733842, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21840583) 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, 3844 + ... + 7645.

It is an arithmetic number, because the mean of its divisors is an integer number (5463495).

Almost surely, 2^21840589 is an apocalyptic number.

It is an amenable number.

21840589 is a deficient number, since it is larger than the sum of its proper divisors (13391).

21840589 is a wasteful number, since it uses less digits than its factorization.

21840589 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13390.

The product of its (nonzero) digits is 23040, while the sum is 37.

The square root of 21840589 is about 4673.3915949768. The cubic root of 21840589 is about 279.5255101561.

The spelling of 21840589 in words is "twenty-one million, eight hundred forty thousand, five hundred eighty-nine".