21315325 has 6 divisors (see below), whose sum is σ = 26431034. Its totient is φ = 17052240.

The previous prime is 21315289. The next prime is 21315341. The reversal of 21315325 is 52351312.

It can be written as a sum of positive squares in 3 ways, for example, as 4782969 + 16532356 = 2187^2 + 4066^2 .

It is not a de Polignac number, because 21315325 - 2¹³ = 21307133 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21315296 and 21315305.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 426282 + ... + 426331.

Almost surely, 2^21315325 is an apocalyptic number.

21315325 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21315325 is a deficient number, since it is larger than the sum of its proper divisors (5115709).

21315325 is an equidigital number, since it uses as much as digits as its factorization.

21315325 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 852623 (or 852618 counting only the distinct ones).

The product of its digits is 900, while the sum is 22.

The square root of 21315325 is about 4616.8522826705. The cubic root of 21315325 is about 277.2664485153.

Adding to 21315325 its reverse (52351312), we get a palindrome (73666637).

The spelling of 21315325 in words is "twenty-one million, three hundred fifteen thousand, three hundred twenty-five".