21895 has 8 divisors (see below), whose sum is σ = 27360. Its totient is φ = 16800.

The previous prime is 21893. The next prime is 21911. The reversal of 21895 is 59812.

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

It is not a de Polignac number, because 21895 - 2¹ = 21893 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21893) 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, 70 + ... + 220.

It is an arithmetic number, because the mean of its divisors is an integer number (3420).

2²¹⁸⁹⁵ is an apocalyptic number.

21895 is a deficient number, since it is larger than the sum of its proper divisors (5465).

21895 is a wasteful number, since it uses less digits than its factorization.

21895 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 185.

The product of its digits is 720, while the sum is 25.

The square root of 21895 is about 147.9695914707. The cubic root of 21895 is about 27.9757443001.

It can be divided in two parts, 218 and 95, that added together give a palindrome (313).

The spelling of 21895 in words is "twenty-one thousand, eight hundred ninety-five".