25679921 has 2 divisors, whose sum is σ = 25679922. Its totient is φ = 25679920.

The previous prime is 25679897. The next prime is 25679923. The reversal of 25679921 is 12997652.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 24750625 + 929296 = 4975^2 + 964^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-25679921 is a prime.

Together with 25679923, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (25679923) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 12839960 + 12839961.

It is an arithmetic number, because the mean of its divisors is an integer number (12839961).

Almost surely, 2^25679921 is an apocalyptic number.

It is an amenable number.

25679921 is a deficient number, since it is larger than the sum of its proper divisors (1).

25679921 is an equidigital number, since it uses as much as digits as its factorization.

25679921 is an evil number, because the sum of its binary digits is even.

The product of its digits is 68040, while the sum is 41.

The square root of 25679921 is about 5067.5359890187. The cubic root of 25679921 is about 295.0289007403.

The spelling of 25679921 in words is "twenty-five million, six hundred seventy-nine thousand, nine hundred twenty-one".