25666709 has 2 divisors, whose sum is σ = 25666710. Its totient is φ = 25666708.

The previous prime is 25666703. The next prime is 25666717. The reversal of 25666709 is 90766652.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 21883684 + 3783025 = 4678^2 + 1945^2 .

It is a cyclic number.

It is not a de Polignac number, because 25666709 - 2¹² = 25662613 is a prime.

It is a Sophie Germain 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 (25666703) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 12833354 + 12833355.

It is an arithmetic number, because the mean of its divisors is an integer number (12833355).

Almost surely, 2^25666709 is an apocalyptic number.

It is an amenable number.

25666709 is a deficient number, since it is larger than the sum of its proper divisors (1).

25666709 is an equidigital number, since it uses as much as digits as its factorization.

25666709 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 136080, while the sum is 41.

The square root of 25666709 is about 5066.2322291818. The cubic root of 25666709 is about 294.9782958273.

The spelling of 25666709 in words is "twenty-five million, six hundred sixty-six thousand, seven hundred nine".