12181666815 has 32 divisors (see below), whose sum is σ = 21666758400. Its totient is φ = 6493750560.

The previous prime is 12181666699. The next prime is 12181666817. The reversal of 12181666815 is 51866618121.

It is not a de Polignac number, because 12181666815 - 2⁹ = 12181666303 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (12181666817) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 273460 + ... + 314870.

It is an arithmetic number, because the mean of its divisors is an integer number (677086200).

Almost surely, 2^12181666815 is an apocalyptic number.

12181666815 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

12181666815 is a deficient number, since it is larger than the sum of its proper divisors (9485091585).

12181666815 is a wasteful number, since it uses less digits than its factorization.

12181666815 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 43604 (or 43598 counting only the distinct ones).

The product of its digits is 138240, while the sum is 45.

The spelling of 12181666815 in words is "twelve billion, one hundred eighty-one million, six hundred sixty-six thousand, eight hundred fifteen".