12187566491 has 4 divisors (see below), whose sum is σ = 12233907312. Its totient is φ = 12141225672.

The previous prime is 12187566481. The next prime is 12187566541. The reversal of 12187566491 is 19466578121.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 19466578121 = 37 ⋅526123733.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-12187566491 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (12187566451) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 23170016 + ... + 23170541.

It is an arithmetic number, because the mean of its divisors is an integer number (3058476828).

Almost surely, 2^12187566491 is an apocalyptic number.

12187566491 is a deficient number, since it is larger than the sum of its proper divisors (46340821).

12187566491 is an equidigital number, since it uses as much as digits as its factorization.

12187566491 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 46340820.

The product of its digits is 725760, while the sum is 50.

The spelling of 12187566491 in words is "twelve billion, one hundred eighty-seven million, five hundred sixty-six thousand, four hundred ninety-one".