25578521 has 2 divisors, whose sum is σ = 25578522. Its totient is φ = 25578520.

The previous prime is 25578517. The next prime is 25578577. The reversal of 25578521 is 12587552.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 13579225 + 11999296 = 3685^2 + 3464^2 .

It is a cyclic number.

It is not a de Polignac number, because 25578521 - 2² = 25578517 is a prime.

It is not a weakly prime, because it can be changed into another prime (25578821) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 12789260 + 12789261.

It is an arithmetic number, because the mean of its divisors is an integer number (12789261).

Almost surely, 2^25578521 is an apocalyptic number.

It is an amenable number.

25578521 is a deficient number, since it is larger than the sum of its proper divisors (1).

25578521 is an equidigital number, since it uses as much as digits as its factorization.

25578521 is an evil number, because the sum of its binary digits is even.

The product of its digits is 28000, while the sum is 35.

The square root of 25578521 is about 5057.5212308007. The cubic root of 25578521 is about 294.6400704607.

The spelling of 25578521 in words is "twenty-five million, five hundred seventy-eight thousand, five hundred twenty-one".