1800120661857 has 24 divisors (see below), whose sum is σ = 3067486722560. Its totient is φ = 995458429440.

The previous prime is 1800120661853. The next prime is 1800120661879. The reversal of 1800120661857 is 7581660210081.

1800120661857 is a `hidden beast` number, since 1 + 8 + 0 + 0 + 1 + 20 + 6 + 618 + 5 + 7 = 666.

It is not a de Polignac number, because 1800120661857 - 2² = 1800120661853 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1800120661853) 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 23 ways as a sum of consecutive naturals, for example, 460858432 + ... + 460862337.

Almost surely, 2^{1800120661857} is an apocalyptic number.

It is an amenable number.

1800120661857 is a deficient number, since it is larger than the sum of its proper divisors (1267366060703).

1800120661857 is a wasteful number, since it uses less digits than its factorization.

1800120661857 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 921720813 (or 921720810 counting only the distinct ones).

The product of its (nonzero) digits is 161280, while the sum is 45.

The spelling of 1800120661857 in words is "one trillion, eight hundred billion, one hundred twenty million, six hundred sixty-one thousand, eight hundred fifty-seven".