21158589 has 8 divisors (see below), whose sum is σ = 28240960. Its totient is φ = 14090976.

The previous prime is 21158563. The next prime is 21158633. The reversal of 21158589 is 98585112.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21158589 - 2¹⁶ = 21093053 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 (21158519) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 264 + ... + 6510.

It is an arithmetic number, because the mean of its divisors is an integer number (3530120).

Almost surely, 2^21158589 is an apocalyptic number.

It is an amenable number.

21158589 is a deficient number, since it is larger than the sum of its proper divisors (7082371).

21158589 is a wasteful number, since it uses less digits than its factorization.

21158589 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7379.

The product of its digits is 28800, while the sum is 39.

The square root of 21158589 is about 4599.8466278779. The cubic root of 21158589 is about 276.5851767227.

The spelling of 21158589 in words is "twenty-one million, one hundred fifty-eight thousand, five hundred eighty-nine".