25778399 has 2 divisors, whose sum is σ = 25778400. Its totient is φ = 25778398.

The previous prime is 25778393. The next prime is 25778407. The reversal of 25778399 is 99387752.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-25778399 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (25778393) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 12889199 + 12889200.

It is an arithmetic number, because the mean of its divisors is an integer number (12889200).

Almost surely, 2^25778399 is an apocalyptic number.

25778399 is a deficient number, since it is larger than the sum of its proper divisors (1).

25778399 is an equidigital number, since it uses as much as digits as its factorization.

25778399 is an evil number, because the sum of its binary digits is even.

The product of its digits is 952560, while the sum is 50.

The square root of 25778399 is about 5077.2432480629. The cubic root of 25778399 is about 295.4055477478.

The spelling of 25778399 in words is "twenty-five million, seven hundred seventy-eight thousand, three hundred ninety-nine".