20904025 has 6 divisors (see below), whose sum is σ = 25921022. Its totient is φ = 16723200.

The previous prime is 20904019. The next prime is 20904031. The reversal of 20904025 is 52040902.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (20904019) and next prime (20904031).

It can be written as a sum of positive squares in 3 ways, for example, as 841 + 20903184 = 29^2 + 4572^2 .

It is not a de Polignac number, because 20904025 - 2³ = 20904017 is a prime.

It is a super-2 number, since 2×20904025² = 873956522401250, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 20903987 and 20904005.

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, 418056 + ... + 418105.

Almost surely, 2^20904025 is an apocalyptic number.

20904025 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

20904025 is a deficient number, since it is larger than the sum of its proper divisors (5016997).

20904025 is an equidigital number, since it uses as much as digits as its factorization.

20904025 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 836171 (or 836166 counting only the distinct ones).

The product of its (nonzero) digits is 720, while the sum is 22.

The square root of 20904025 is about 4572.0919719533. The cubic root of 20904025 is about 275.4714777077.

Adding to 20904025 its reverse (52040902), we get a palindrome (72944927).

The spelling of 20904025 in words is "twenty million, nine hundred four thousand, twenty-five".