12661215820818 has 8 divisors (see below), whose sum is σ = 25322431641648. Its totient is φ = 4220405273604.

The previous prime is 12661215820793. The next prime is 12661215820829. The reversal of 12661215820818 is 81802851216621.

12661215820818 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a sphenic number, since it is the product of 3 distinct primes.

12661215820818 is an admirable number.

It is a super-2 number, since 2×12661215820818² (a number of 27 digits) contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1055101318396 + ... + 1055101318407.

It is an arithmetic number, because the mean of its divisors is an integer number (3165303955206).

Almost surely, 2^{12661215820818} is an apocalyptic number.

12661215820818 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

12661215820818 is a wasteful number, since it uses less digits than its factorization.

12661215820818 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2110202636808.

The product of its (nonzero) digits is 737280, while the sum is 51.

The spelling of 12661215820818 in words is "twelve trillion, six hundred sixty-one billion, two hundred fifteen million, eight hundred twenty thousand, eight hundred eighteen".