25559865 has 12 divisors (see below), whose sum is σ = 44303844. Its totient is φ = 13631904.

The previous prime is 25559861. The next prime is 25559879. The reversal of 25559865 is 56895552.

25559865 is a `hidden beast` number, since 2 + 55 + 598 + 6 + 5 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 15139881 + 10419984 = 3891^2 + 3228^2 .

It is not a de Polignac number, because 25559865 - 2² = 25559861 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (45), and also a Moran number because the ratio is a prime number: 567997 = 25559865 / (2 + 5 + 5 + 5 + 9 + 8 + 6 + 5).

It is a self number, because there is not a number n which added to its sum of digits gives 25559865.

It is not an unprimeable number, because it can be changed into a prime (25559861) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 283954 + ... + 284043.

It is an arithmetic number, because the mean of its divisors is an integer number (3691987).

Almost surely, 2^25559865 is an apocalyptic number.

It is an amenable number.

25559865 is a deficient number, since it is larger than the sum of its proper divisors (18743979).

25559865 is a wasteful number, since it uses less digits than its factorization.

25559865 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 568008 (or 568005 counting only the distinct ones).

The product of its digits is 540000, while the sum is 45.

The square root of 25559865 is about 5055.6765125945. The cubic root of 25559865 is about 294.5684199525.

It can be divided in two parts, 255 and 59865, that multiplied together give a triangular number (15265575 = T₅₅₂₅).

The spelling of 25559865 in words is "twenty-five million, five hundred fifty-nine thousand, eight hundred sixty-five".