25918649 has 2 divisors, whose sum is σ = 25918650. Its totient is φ = 25918648.

The previous prime is 25918639. The next prime is 25918661. The reversal of 25918649 is 94681952.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 25050025 + 868624 = 5005^2 + 932^2 .

It is a cyclic number.

It is not a de Polignac number, because 25918649 - 2⁸ = 25918393 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (25918609) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 12959324 + 12959325.

It is an arithmetic number, because the mean of its divisors is an integer number (12959325).

Almost surely, 2^25918649 is an apocalyptic number.

It is an amenable number.

25918649 is a deficient number, since it is larger than the sum of its proper divisors (1).

25918649 is an equidigital number, since it uses as much as digits as its factorization.

25918649 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 155520, while the sum is 44.

The square root of 25918649 is about 5091.0361420835. The cubic root of 25918649 is about 295.9403070826.

The spelling of 25918649 in words is "twenty-five million, nine hundred eighteen thousand, six hundred forty-nine".