25891665 has 16 divisors (see below), whose sum is σ = 42763776. Its totient is φ = 13363200.

The previous prime is 25891639. The next prime is 25891667. The reversal of 25891665 is 56619852.

It is not a de Polignac number, because 25891665 - 2¹⁴ = 25875281 is a prime.

It is not an unprimeable number, because it can be changed into a prime (25891667) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 27376 + ... + 28305.

It is an arithmetic number, because the mean of its divisors is an integer number (2672736).

Almost surely, 2^25891665 is an apocalyptic number.

It is an amenable number.

25891665 is a deficient number, since it is larger than the sum of its proper divisors (16872111).

25891665 is a wasteful number, since it uses less digits than its factorization.

25891665 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 55720.

The product of its digits is 129600, while the sum is 42.

The square root of 25891665 is about 5088.3853038071. The cubic root of 25891665 is about 295.8375699100.

The spelling of 25891665 in words is "twenty-five million, eight hundred ninety-one thousand, six hundred sixty-five".