12181561550 has 12 divisors (see below), whose sum is σ = 22657704576. Its totient is φ = 4872624600.

The previous prime is 12181561501. The next prime is 12181561577. The reversal of 12181561550 is 5516518121.

12181561550 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a self number, because there is not a number n which added to its sum of digits gives 12181561550.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 121815566 + ... + 121815665.

It is an arithmetic number, because the mean of its divisors is an integer number (1888142048).

Almost surely, 2^12181561550 is an apocalyptic number.

12181561550 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

12181561550 is a deficient number, since it is larger than the sum of its proper divisors (10476143026).

12181561550 is a wasteful number, since it uses less digits than its factorization.

12181561550 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 243631243 (or 243631238 counting only the distinct ones).

The product of its (nonzero) digits is 12000, while the sum is 35.

The spelling of 12181561550 in words is "twelve billion, one hundred eighty-one million, five hundred sixty-one thousand, five hundred fifty".