21586 has 8 divisors (see below), whose sum is σ = 33264. Its totient is φ = 10500.

The previous prime is 21577. The next prime is 21587. The reversal of 21586 is 68512.

It is a happy number.

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

It is not an unprimeable number, because it can be changed into a prime (21587) 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, 40 + ... + 211.

It is an arithmetic number, because the mean of its divisors is an integer number (4158).

21586 is a Friedman number, since it can be written as 251*86, using all its digits and the basic arithmetic operations.

2²¹⁵⁸⁶ is an apocalyptic number.

21586 is a deficient number, since it is larger than the sum of its proper divisors (11678).

21586 is a wasteful number, since it uses less digits than its factorization.

21586 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 296.

The product of its digits is 480, while the sum is 22.

The square root of 21586 is about 146.9217478796. The cubic root of 21586 is about 27.8435148269.

The spelling of 21586 in words is "twenty-one thousand, five hundred eighty-six".