12615405555818 has 64 divisors (see below), whose sum is σ = 22275483783840. Its totient is φ = 5304259510272.

The previous prime is 12615405555817. The next prime is 12615405555877. The reversal of 12615405555818 is 81855550451621.

It can be written as a sum of positive squares in 16 ways, for example, as 5368363882729 + 7247041673089 = 2316973^2 + 2692033^2 .

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (12615405555811) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 1157888 + ... + 5154756.

Almost surely, 2^{12615405555818} is an apocalyptic number.

12615405555818 is a deficient number, since it is larger than the sum of its proper divisors (9660078228022).

12615405555818 is a wasteful number, since it uses less digits than its factorization.

12615405555818 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3997131.

The product of its (nonzero) digits is 9600000, while the sum is 56.

The spelling of 12615405555818 in words is "twelve trillion, six hundred fifteen billion, four hundred five million, five hundred fifty-five thousand, eight hundred eighteen".