25515509 has 2 divisors, whose sum is σ = 25515510. Its totient is φ = 25515508.

The previous prime is 25515493. The next prime is 25515551. The reversal of 25515509 is 90551552.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 13853284 + 11662225 = 3722^2 + 3415^2 .

It is a cyclic number.

It is not a de Polignac number, because 25515509 - 2⁴ = 25515493 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (25515109) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 12757754 + 12757755.

It is an arithmetic number, because the mean of its divisors is an integer number (12757755).

Almost surely, 2^25515509 is an apocalyptic number.

It is an amenable number.

25515509 is a deficient number, since it is larger than the sum of its proper divisors (1).

25515509 is an equidigital number, since it uses as much as digits as its factorization.

25515509 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 11250, while the sum is 32.

The square root of 25515509 is about 5051.2878555869. The cubic root of 25515509 is about 294.3979255439.

The spelling of 25515509 in words is "twenty-five million, five hundred fifteen thousand, five hundred nine".