12687391 has 4 divisors (see below), whose sum is σ = 12751992. Its totient is φ = 12622792.

The previous prime is 12687379. The next prime is 12687439. The reversal of 12687391 is 19378621.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 19378621 = 79 ⋅245299.

It is a cyclic number.

It is not a de Polignac number, because 12687391 - 2⁵ = 12687359 is a prime.

It is a Duffinian number.

It is a zygodrome in base 2.

It is a self number, because there is not a number n which added to its sum of digits gives 12687391.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (12687331) 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 3 ways as a sum of consecutive naturals, for example, 32005 + ... + 32398.

It is an arithmetic number, because the mean of its divisors is an integer number (3187998).

Almost surely, 2^12687391 is an apocalyptic number.

12687391 is a deficient number, since it is larger than the sum of its proper divisors (64601).

12687391 is an equidigital number, since it uses as much as digits as its factorization.

12687391 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 64600.

The product of its digits is 18144, while the sum is 37.

The square root of 12687391 is about 3561.9364115604. The cubic root of 12687391 is about 233.2334168577.

The spelling of 12687391 in words is "twelve million, six hundred eighty-seven thousand, three hundred ninety-one".