25660891 has 4 divisors (see below), whose sum is σ = 26022384. Its totient is φ = 25299400.

The previous prime is 25660883. The next prime is 25660937. The reversal of 25660891 is 19806652.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 25660891 - 2³ = 25660883 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 25660891.

It is not an unprimeable number, because it can be changed into a prime (25660091) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 180640 + ... + 180781.

It is an arithmetic number, because the mean of its divisors is an integer number (6505596).

Almost surely, 2^25660891 is an apocalyptic number.

25660891 is a deficient number, since it is larger than the sum of its proper divisors (361493).

25660891 is an equidigital number, since it uses as much as digits as its factorization.

25660891 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 361492.

The product of its (nonzero) digits is 25920, while the sum is 37.

The square root of 25660891 is about 5065.6580026686. The cubic root of 25660891 is about 294.9560060795.

The spelling of 25660891 in words is "twenty-five million, six hundred sixty thousand, eight hundred ninety-one".