25815613 has 2 divisors, whose sum is σ = 25815614. Its totient is φ = 25815612.

The previous prime is 25815593. The next prime is 25815617. The reversal of 25815613 is 31651852.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 22867524 + 2948089 = 4782^2 + 1717^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-25815613 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (25815617) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 12907806 + 12907807.

It is an arithmetic number, because the mean of its divisors is an integer number (12907807).

Almost surely, 2^25815613 is an apocalyptic number.

It is an amenable number.

25815613 is a deficient number, since it is larger than the sum of its proper divisors (1).

25815613 is an equidigital number, since it uses as much as digits as its factorization.

25815613 is an evil number, because the sum of its binary digits is even.

The product of its digits is 7200, while the sum is 31.

The square root of 25815613 is about 5080.9067104209. The cubic root of 25815613 is about 295.5476297071.

The spelling of 25815613 in words is "twenty-five million, eight hundred fifteen thousand, six hundred thirteen".