25578409 has 2 divisors, whose sum is σ = 25578410. Its totient is φ = 25578408.

The previous prime is 25578407. The next prime is 25578431. The reversal of 25578409 is 90487552.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 24970009 + 608400 = 4997^2 + 780^2 .

It is a cyclic number.

It is not a de Polignac number, because 25578409 - 2¹ = 25578407 is a prime.

Together with 25578407, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (25578407) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 12789204 + 12789205.

It is an arithmetic number, because the mean of its divisors is an integer number (12789205).

Almost surely, 2^25578409 is an apocalyptic number.

It is an amenable number.

25578409 is a deficient number, since it is larger than the sum of its proper divisors (1).

25578409 is an equidigital number, since it uses as much as digits as its factorization.

25578409 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 100800, while the sum is 40.

The square root of 25578409 is about 5057.5101581707. The cubic root of 25578409 is about 294.6396404158.

The spelling of 25578409 in words is "twenty-five million, five hundred seventy-eight thousand, four hundred nine".