12391643 has 4 divisors (see below), whose sum is σ = 13518168. Its totient is φ = 11265120.

The previous prime is 12391637. The next prime is 12391649. The reversal of 12391643 is 34619321.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 34619321 = 11 ⋅3147211.

It is an interprime number because it is at equal distance from previous prime (12391637) and next prime (12391649).

It is a cyclic number.

It is not a de Polignac number, because 12391643 - 2⁴ = 12391627 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (12391649) 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, 563246 + ... + 563267.

It is an arithmetic number, because the mean of its divisors is an integer number (3379542).

Almost surely, 2^12391643 is an apocalyptic number.

12391643 is a deficient number, since it is larger than the sum of its proper divisors (1126525).

12391643 is a wasteful number, since it uses less digits than its factorization.

12391643 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1126524.

The product of its digits is 3888, while the sum is 29.

The square root of 12391643 is about 3520.1765580721. The cubic root of 12391643 is about 231.4068963994.

It can be divided in two parts, 1239 and 1643, that added together give a palindrome (2882).

The spelling of 12391643 in words is "twelve million, three hundred ninety-one thousand, six hundred forty-three".