25563891 has 4 divisors (see below), whose sum is σ = 34085192. Its totient is φ = 17042592.

The previous prime is 25563841. The next prime is 25563893. The reversal of 25563891 is 19836552.

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

It is not a de Polignac number, because 25563891 - 2⁶ = 25563827 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (25563893) 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, 4260646 + ... + 4260651.

It is an arithmetic number, because the mean of its divisors is an integer number (8521298).

Almost surely, 2^25563891 is an apocalyptic number.

25563891 is a deficient number, since it is larger than the sum of its proper divisors (8521301).

25563891 is an equidigital number, since it uses as much as digits as its factorization.

25563891 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8521300.

The product of its digits is 64800, while the sum is 39.

The square root of 25563891 is about 5056.0746632145. The cubic root of 25563891 is about 294.5838852167.

It can be divided in two parts, 255 and 63891, that added together give a palindrome (64146).

The spelling of 25563891 in words is "twenty-five million, five hundred sixty-three thousand, eight hundred ninety-one".