21090325 has 6 divisors (see below), whose sum is σ = 26152034. Its totient is φ = 16872240.

The previous prime is 21090299. The next prime is 21090341. The reversal of 21090325 is 52309012.

It can be written as a sum of positive squares in 3 ways, for example, as 86436 + 21003889 = 294^2 + 4583^2 .

It is not a de Polignac number, because 21090325 - 2⁷ = 21090197 is a prime.

It is an alternating number because its digits alternate between even and odd.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21090296 and 21090305.

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, 421782 + ... + 421831.

Almost surely, 2^21090325 is an apocalyptic number.

21090325 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21090325 is a deficient number, since it is larger than the sum of its proper divisors (5061709).

21090325 is an equidigital number, since it uses as much as digits as its factorization.

21090325 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 843623 (or 843618 counting only the distinct ones).

The product of its (nonzero) digits is 540, while the sum is 22.

The square root of 21090325 is about 4592.4203858096. The cubic root of 21090325 is about 276.2874071496.

Adding to 21090325 its reverse (52309012), we get a palindrome (73399337).

The spelling of 21090325 in words is "twenty-one million, ninety thousand, three hundred twenty-five".