25991865 has 24 divisors (see below), whose sum is σ = 45601920. Its totient is φ = 13693344.

The previous prime is 25991851. The next prime is 25991879. The reversal of 25991865 is 56819952.

It is an interprime number because it is at equal distance from previous prime (25991851) and next prime (25991879).

It is not a de Polignac number, because 25991865 - 2²² = 21797561 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 25991865.

It is an unprimeable number.

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 in 23 ways as a sum of consecutive naturals, for example, 256 + ... + 7214.

It is an arithmetic number, because the mean of its divisors is an integer number (1900080).

Almost surely, 2^25991865 is an apocalyptic number.

It is an amenable number.

25991865 is a deficient number, since it is larger than the sum of its proper divisors (19610055).

25991865 is a wasteful number, since it uses less digits than its factorization.

25991865 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7053 (or 7050 counting only the distinct ones).

The product of its digits is 194400, while the sum is 45.

The square root of 25991865 is about 5098.2217488061. The cubic root of 25991865 is about 296.2187063030.

The spelling of 25991865 in words is "twenty-five million, nine hundred ninety-one thousand, eight hundred sixty-five".