21925 has 6 divisors (see below), whose sum is σ = 27218. Its totient is φ = 17520.

The previous prime is 21911. The next prime is 21929. The reversal of 21925 is 52912.

21925 is digitally balanced in base 6, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 3 ways, for example, as 3969 + 17956 = 63^2 + 134^2 .

It is not a de Polignac number, because 21925 - 2⁵ = 21893 is a prime.

It is a Duffinian number.

21925 is strictly pandigital in base 6.

21925 is a lucky number.

It is a zygodrome in base 4.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21929) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 414 + ... + 463.

2²¹⁹²⁵ is an apocalyptic number.

21925 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21925 is a deficient number, since it is larger than the sum of its proper divisors (5293).

21925 is an equidigital number, since it uses as much as digits as its factorization.

21925 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 887 (or 882 counting only the distinct ones).

The product of its digits is 180, while the sum is 19.

The square root of 21925 is about 148.0709289496. The cubic root of 21925 is about 27.9885156985.

It can be divided in two parts, 2192 and 5, that added together give a cube (2197 = 13³).

The spelling of 21925 in words is "twenty-one thousand, nine hundred twenty-five".