25947221 has 2 divisors, whose sum is σ = 25947222. Its totient is φ = 25947220.

The previous prime is 25947191. The next prime is 25947223. The reversal of 25947221 is 12274952.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 23902321 + 2044900 = 4889^2 + 1430^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-25947221 is a prime.

It is a Sophie Germain prime.

Together with 25947223, it forms a pair of twin primes.

It is a Chen prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (25947223) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 12973610 + 12973611.

It is an arithmetic number, because the mean of its divisors is an integer number (12973611).

Almost surely, 2^25947221 is an apocalyptic number.

It is an amenable number.

25947221 is a deficient number, since it is larger than the sum of its proper divisors (1).

25947221 is an equidigital number, since it uses as much as digits as its factorization.

25947221 is an evil number, because the sum of its binary digits is even.

The product of its digits is 10080, while the sum is 32.

The square root of 25947221 is about 5093.8414777062. The cubic root of 25947221 is about 296.0490126107.

The spelling of 25947221 in words is "twenty-five million, nine hundred forty-seven thousand, two hundred twenty-one".