25978649 has 2 divisors, whose sum is σ = 25978650. Its totient is φ = 25978648.

The previous prime is 25978627. The next prime is 25978663. The reversal of 25978649 is 94687952.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 25938649 + 40000 = 5093^2 + 200^2 .

It is a cyclic number.

It is not a de Polignac number, because 25978649 - 2¹⁶ = 25913113 is a prime.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 25978597 and 25978606.

It is not a weakly prime, because it can be changed into another prime (25978609) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 12989324 + 12989325.

It is an arithmetic number, because the mean of its divisors is an integer number (12989325).

Almost surely, 2^25978649 is an apocalyptic number.

It is an amenable number.

25978649 is a deficient number, since it is larger than the sum of its proper divisors (1).

25978649 is an equidigital number, since it uses as much as digits as its factorization.

25978649 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1088640, while the sum is 50.

The square root of 25978649 is about 5096.9254457957. The cubic root of 25978649 is about 296.1684920003.

The spelling of 25978649 in words is "twenty-five million, nine hundred seventy-eight thousand, six hundred forty-nine".