21147325 has 6 divisors (see below), whose sum is σ = 26222714. Its totient is φ = 16917840.

The previous prime is 21147319. The next prime is 21147341. The reversal of 21147325 is 52374112.

It is a happy number.

It can be written as a sum of positive squares in 3 ways, for example, as 1734489 + 19412836 = 1317^2 + 4406^2 .

It is not a de Polignac number, because 21147325 - 2³ = 21147317 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (25), and also a Moran number because the ratio is a prime number: 845893 = 21147325 / (2 + 1 + 1 + 4 + 7 + 3 + 2 + 5).

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21147325.

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, 422922 + ... + 422971.

Almost surely, 2^21147325 is an apocalyptic number.

21147325 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21147325 is a deficient number, since it is larger than the sum of its proper divisors (5075389).

21147325 is an equidigital number, since it uses as much as digits as its factorization.

21147325 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 845903 (or 845898 counting only the distinct ones).

The product of its digits is 1680, while the sum is 25.

The square root of 21147325 is about 4598.6220762311. The cubic root of 21147325 is about 276.5360869899.

It can be divided in two parts, 211473 and 25, that multiplied together give a palindrome (5286825).

The spelling of 21147325 in words is "twenty-one million, one hundred forty-seven thousand, three hundred twenty-five".