25681321 has 2 divisors, whose sum is σ = 25681322. Its totient is φ = 25681320.

The previous prime is 25681319. The next prime is 25681333. The reversal of 25681321 is 12318652.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 25613721 + 67600 = 5061^2 + 260^2 .

It is a cyclic number.

It is not a de Polignac number, because 25681321 - 2¹ = 25681319 is a prime.

Together with 25681319, it forms a pair of twin primes.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 25681321.

It is not a weakly prime, because it can be changed into another prime (25681351) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 12840660 + 12840661.

It is an arithmetic number, because the mean of its divisors is an integer number (12840661).

Almost surely, 2^25681321 is an apocalyptic number.

It is an amenable number.

25681321 is a deficient number, since it is larger than the sum of its proper divisors (1).

25681321 is an equidigital number, since it uses as much as digits as its factorization.

25681321 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2880, while the sum is 28.

The square root of 25681321 is about 5067.6741213302. The cubic root of 25681321 is about 295.0342620361.

Adding to 25681321 its reverse (12318652), we get a palindrome (37999973).

The spelling of 25681321 in words is "twenty-five million, six hundred eighty-one thousand, three hundred twenty-one".