25815397 has 2 divisors, whose sum is σ = 25815398. Its totient is φ = 25815396.

The previous prime is 25815389. The next prime is 25815409. The reversal of 25815397 is 79351852.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 17715681 + 8099716 = 4209^2 + 2846^2 .

It is a cyclic number.

It is not a de Polignac number, because 25815397 - 2³ = 25815389 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (25815337) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 12907698 + 12907699.

It is an arithmetic number, because the mean of its divisors is an integer number (12907699).

Almost surely, 2^25815397 is an apocalyptic number.

It is an amenable number.

25815397 is a deficient number, since it is larger than the sum of its proper divisors (1).

25815397 is an equidigital number, since it uses as much as digits as its factorization.

25815397 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 75600, while the sum is 40.

The square root of 25815397 is about 5080.8854543278. The cubic root of 25815397 is about 295.5468054195.

The spelling of 25815397 in words is "twenty-five million, eight hundred fifteen thousand, three hundred ninety-seven".