12659212778 has 4 divisors (see below), whose sum is σ = 18988819170. Its totient is φ = 6329606388.

The previous prime is 12659212757. The next prime is 12659212789. The reversal of 12659212778 is 87721295621.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 87721295621 = 17 ⋅5160076213.

It can be written as a sum of positive squares in only one way, i.e., 11684961409 + 974251369 = 108097^2 + 31213^2 .

It is a Curzon number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3164803193 + ... + 3164803196.

Almost surely, 2^12659212778 is an apocalyptic number.

12659212778 is a deficient number, since it is larger than the sum of its proper divisors (6329606392).

12659212778 is an equidigital number, since it uses as much as digits as its factorization.

12659212778 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6329606391.

The product of its digits is 846720, while the sum is 50.

The spelling of 12659212778 in words is "twelve billion, six hundred fifty-nine million, two hundred twelve thousand, seven hundred seventy-eight".