25666391 has 2 divisors, whose sum is σ = 25666392. Its totient is φ = 25666390.

The previous prime is 25666387. The next prime is 25666409. The reversal of 25666391 is 19366652.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 25666391 - 2² = 25666387 is a prime.

It is a Sophie Germain prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (25666331) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 12833195 + 12833196.

It is an arithmetic number, because the mean of its divisors is an integer number (12833196).

Almost surely, 2^25666391 is an apocalyptic number.

25666391 is a deficient number, since it is larger than the sum of its proper divisors (1).

25666391 is an equidigital number, since it uses as much as digits as its factorization.

25666391 is an evil number, because the sum of its binary digits is even.

The product of its digits is 58320, while the sum is 38.

The square root of 25666391 is about 5066.2008448146. The cubic root of 25666391 is about 294.9770776022.

The spelling of 25666391 in words is "twenty-five million, six hundred sixty-six thousand, three hundred ninety-one".