21459 has 8 divisors (see below), whose sum is σ = 29952. Its totient is φ = 13640.

The previous prime is 21433. The next prime is 21467. The reversal of 21459 is 95412.

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

It is a cyclic number.

It is not a de Polignac number, because 21459 - 2⁹ = 20947 is a prime.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 21459.

It is not an unprimeable number, because it can be changed into a prime (21419) 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, 87 + ... + 224.

It is an arithmetic number, because the mean of its divisors is an integer number (3744).

2²¹⁴⁵⁹ is an apocalyptic number.

21459 is a deficient number, since it is larger than the sum of its proper divisors (8493).

21459 is a wasteful number, since it uses less digits than its factorization.

21459 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 337.

The product of its digits is 360, while the sum is 21.

The square root of 21459 is about 146.4889074299. The cubic root of 21459 is about 27.7888021426.

The spelling of 21459 in words is "twenty-one thousand, four hundred fifty-nine".