21542589 has 24 divisors (see below), whose sum is σ = 32323200. Its totient is φ = 13815360.

The previous prime is 21542579. The next prime is 21542597. The reversal of 21542589 is 98524512.

21542589 is a `hidden beast` number, since 21 + 54 + 2 + 589 = 666.

It is not a de Polignac number, because 21542589 - 2¹² = 21538493 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21542579) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 28782 + ... + 29520.

It is an arithmetic number, because the mean of its divisors is an integer number (1346800).

Almost surely, 2^21542589 is an apocalyptic number.

It is an amenable number.

21542589 is a deficient number, since it is larger than the sum of its proper divisors (10780611).

21542589 is a wasteful number, since it uses less digits than its factorization.

21542589 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 865 (or 862 counting only the distinct ones).

The product of its digits is 28800, while the sum is 36.

The square root of 21542589 is about 4641.3994656784. The cubic root of 21542589 is about 278.2483719630.

The spelling of 21542589 in words is "twenty-one million, five hundred forty-two thousand, five hundred eighty-nine".