12378781663 has 4 divisors (see below), whose sum is σ = 12379444000. Its totient is φ = 12378119328.

The previous prime is 12378781643. The next prime is 12378781669. The reversal of 12378781663 is 36618787321.

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

It is a cyclic number.

It is not a de Polignac number, because 12378781663 - 2²⁵ = 12345227231 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 12378781663.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (12378781669) 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, 302295 + ... + 340792.

It is an arithmetic number, because the mean of its divisors is an integer number (3094861000).

Almost surely, 2^12378781663 is an apocalyptic number.

12378781663 is a deficient number, since it is larger than the sum of its proper divisors (662337).

12378781663 is an equidigital number, since it uses as much as digits as its factorization.

12378781663 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 662336.

The product of its digits is 2032128, while the sum is 52.

The spelling of 12378781663 in words is "twelve billion, three hundred seventy-eight million, seven hundred eighty-one thousand, six hundred sixty-three".