25604021 has 2 divisors, whose sum is σ = 25604022. Its totient is φ = 25604020.

The previous prime is 25604009. The next prime is 25604027. The reversal of 25604021 is 12040652.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 24900100 + 703921 = 4990^2 + 839^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-25604021 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is equal to p_1601282 and since 25604021 and 1601282 have the same sum of digits, it is a Honaker prime.

It is a junction number, because it is equal to n+sod(n) for n = 25603984 and 25604002.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (25604027) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 12802010 + 12802011.

It is an arithmetic number, because the mean of its divisors is an integer number (12802011).

Almost surely, 2^25604021 is an apocalyptic number.

It is an amenable number.

25604021 is a deficient number, since it is larger than the sum of its proper divisors (1).

25604021 is an equidigital number, since it uses as much as digits as its factorization.

25604021 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 480, while the sum is 20.

The square root of 25604021 is about 5060.0416006195. The cubic root of 25604021 is about 294.7379498028.

Adding to 25604021 its reverse (12040652), we get a palindrome (37644673).

The spelling of 25604021 in words is "twenty-five million, six hundred four thousand, twenty-one".