12563891 has 4 divisors (see below), whose sum is σ = 12585672. Its totient is φ = 12542112.

The previous prime is 12563857. The next prime is 12563927. The reversal of 12563891 is 19836521.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 19836521 = 197 ⋅100693.

It is a cyclic number.

It is not a de Polignac number, because 12563891 - 2²² = 8369587 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (12563821) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 10001 + ... + 11186.

It is an arithmetic number, because the mean of its divisors is an integer number (3146418).

Almost surely, 2^12563891 is an apocalyptic number.

12563891 is a deficient number, since it is larger than the sum of its proper divisors (21781).

12563891 is an equidigital number, since it uses as much as digits as its factorization.

12563891 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 21780.

The product of its digits is 12960, while the sum is 35.

The square root of 12563891 is about 3544.5579414082. The cubic root of 12563891 is about 232.4741775769.

The spelling of 12563891 in words is "twelve million, five hundred sixty-three thousand, eight hundred ninety-one".