21325 has 6 divisors (see below), whose sum is σ = 26474. Its totient is φ = 17040.

The previous prime is 21323. The next prime is 21341. The reversal of 21325 is 52312.

21325 is nontrivially palindromic in base 8.

It can be written as a sum of positive squares in 3 ways, for example, as 9 + 21316 = 3^2 + 146^2 .

It is not a de Polignac number, because 21325 - 2¹ = 21323 is a prime.

It is an Ulam number.

It is a Duffinian number.

21325 is an undulating number in base 8.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21323) 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, 402 + ... + 451.

2²¹³²⁵ is an apocalyptic number.

21325 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21325 is a deficient number, since it is larger than the sum of its proper divisors (5149).

21325 is an equidigital number, since it uses as much as digits as its factorization.

21325 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 863 (or 858 counting only the distinct ones).

The product of its digits is 60, while the sum is 13.

The square root of 21325 is about 146.0308186651. The cubic root of 21325 is about 27.7308392471.

Subtracting from 21325 its sum of digits (13), we obtain a palindrome (21312).

Adding to 21325 its reverse (52312), we get a palindrome (73637).

The spelling of 21325 in words is "twenty-one thousand, three hundred twenty-five".