21312325 has 12 divisors (see below), whose sum is σ = 26748288. Its totient is φ = 16842800.

The previous prime is 21312323. The next prime is 21312337. The reversal of 21312325 is 52321312.

It is not a de Polignac number, because 21312325 - 2¹ = 21312323 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21312323) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 3061 + ... + 7210.

It is an arithmetic number, because the mean of its divisors is an integer number (2229024).

Almost surely, 2^21312325 is an apocalyptic number.

21312325 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21312325 is a deficient number, since it is larger than the sum of its proper divisors (5435963).

21312325 is a wasteful number, since it uses less digits than its factorization.

21312325 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10364 (or 10359 counting only the distinct ones).

The product of its digits is 360, while the sum is 19.

The square root of 21312325 is about 4616.5273745533. The cubic root of 21312325 is about 277.2534400598.

Adding to 21312325 its reverse (52321312), we get a palindrome (73633637).

The spelling of 21312325 in words is "twenty-one million, three hundred twelve thousand, three hundred twenty-five".