25921691 has 2 divisors, whose sum is σ = 25921692. Its totient is φ = 25921690.

The previous prime is 25921661. The next prime is 25921711. The reversal of 25921691 is 19612952.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 25921691 - 2⁶ = 25921627 is a prime.

It is not a weakly prime, because it can be changed into another prime (25921631) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 12960845 + 12960846.

It is an arithmetic number, because the mean of its divisors is an integer number (12960846).

Almost surely, 2^25921691 is an apocalyptic number.

25921691 is a deficient number, since it is larger than the sum of its proper divisors (1).

25921691 is an equidigital number, since it uses as much as digits as its factorization.

25921691 is an evil number, because the sum of its binary digits is even.

The product of its digits is 9720, while the sum is 35.

The square root of 25921691 is about 5091.3348937189. The cubic root of 25921691 is about 295.9518845276.

The spelling of 25921691 in words is "twenty-five million, nine hundred twenty-one thousand, six hundred ninety-one".