12561778850 has 24 divisors (see below), whose sum is σ = 23934788388. Its totient is φ = 4902156800.

The previous prime is 12561778849. The next prime is 12561778897. The reversal of 12561778850 is 5887716521.

12561778850 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 6 ways, for example, as 1380196801 + 11181582049 = 37151^2 + 105743^2 .

It is a hoax number, since the sum of its digits (50) coincides with the sum of the digits of its distinct prime factors.

It is a Harshad number since it is a multiple of its sum of digits (50).

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 11 ways as a sum of consecutive naturals, for example, 3061799 + ... + 3065898.

Almost surely, 2^12561778850 is an apocalyptic number.

12561778850 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

12561778850 is a deficient number, since it is larger than the sum of its proper divisors (11373009538).

12561778850 is a wasteful number, since it uses less digits than its factorization.

12561778850 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6127750 (or 6127745 counting only the distinct ones).

The product of its (nonzero) digits is 940800, while the sum is 50.

The spelling of 12561778850 in words is "twelve billion, five hundred sixty-one million, seven hundred seventy-eight thousand, eight hundred fifty".