25778450491 has 2 divisors, whose sum is σ = 25778450492. Its totient is φ = 25778450490.

The previous prime is 25778450459. The next prime is 25778450513. The reversal of 25778450491 is 19405487752.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 25778450491 - 2⁵ = 25778450459 is a prime.

It is not a weakly prime, because it can be changed into another prime (25778459491) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 12889225245 + 12889225246.

It is an arithmetic number, because the mean of its divisors is an integer number (12889225246).

Almost surely, 2^25778450491 is an apocalyptic number.

25778450491 is a deficient number, since it is larger than the sum of its proper divisors (1).

25778450491 is an equidigital number, since it uses as much as digits as its factorization.

25778450491 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2822400, while the sum is 52.

The spelling of 25778450491 in words is "twenty-five billion, seven hundred seventy-eight million, four hundred fifty thousand, four hundred ninety-one".