25918561 has 2 divisors, whose sum is σ = 25918562. Its totient is φ = 25918560.

The previous prime is 25918553. The next prime is 25918579. The reversal of 25918561 is 16581952.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 25401600 + 516961 = 5040^2 + 719^2 .

It is a cyclic number.

It is not a de Polignac number, because 25918561 - 2³ = 25918553 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 25918561.

It is not a weakly prime, because it can be changed into another prime (25918661) 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, 12959280 + 12959281.

It is an arithmetic number, because the mean of its divisors is an integer number (12959281).

Almost surely, 2^25918561 is an apocalyptic number.

It is an amenable number.

25918561 is a deficient number, since it is larger than the sum of its proper divisors (1).

25918561 is an equidigital number, since it uses as much as digits as its factorization.

25918561 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 21600, while the sum is 37.

The square root of 25918561 is about 5091.0274994347. The cubic root of 25918561 is about 295.9399721529.

The spelling of 25918561 in words is "twenty-five million, nine hundred eighteen thousand, five hundred sixty-one".