21240325 has 12 divisors (see below), whose sum is σ = 27247140. Its totient is φ = 16405760.

The previous prime is 21240313. The next prime is 21240377. The reversal of 21240325 is 52304212.

It can be written as a sum of positive squares in 6 ways, for example, as 15876 + 21224449 = 126^2 + 4607^2 .

It is not a de Polignac number, because 21240325 - 2¹¹ = 21238277 is a prime.

It is a super-2 number, since 2×21240325² = 902302812211250, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 13924 + ... + 15373.

It is an arithmetic number, because the mean of its divisors is an integer number (2270595).

Almost surely, 2^21240325 is an apocalyptic number.

21240325 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21240325 is a deficient number, since it is larger than the sum of its proper divisors (6006815).

21240325 is a wasteful number, since it uses less digits than its factorization.

21240325 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 29336 (or 29331 counting only the distinct ones).

The product of its (nonzero) digits is 480, while the sum is 19.

The square root of 21240325 is about 4608.7227080830. The cubic root of 21240325 is about 276.9408702262.

Adding to 21240325 its reverse (52304212), we get a palindrome (73544537).

The spelling of 21240325 in words is "twenty-one million, two hundred forty thousand, three hundred twenty-five".