218271803855661 has 64 divisors (see below), whose sum is σ = 338975288279040. Its totient is φ = 138548464528320.

The previous prime is 218271803855509. The next prime is 218271803855663. The reversal of 218271803855661 is 166558308172812.

It is a happy number.

218271803855661 is a `hidden beast` number, since 2 + 1 + 8 + 2 + 7 + 18 + 0 + 3 + 8 + 556 + 61 = 666.

It is not a de Polignac number, because 218271803855661 - 2³⁰ = 218270730113837 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (218271803855663) 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 63 ways as a sum of consecutive naturals, for example, 1337802690 + ... + 1337965836.

It is an arithmetic number, because the mean of its divisors is an integer number (5296488879360).

Almost surely, 2^{218271803855661} is an apocalyptic number.

It is an amenable number.

218271803855661 is a deficient number, since it is larger than the sum of its proper divisors (120703484423379).

218271803855661 is a wasteful number, since it uses less digits than its factorization.

218271803855661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 173063 (or 173057 counting only the distinct ones).

The product of its (nonzero) digits is 38707200, while the sum is 63.

The spelling of 218271803855661 in words is "two hundred eighteen trillion, two hundred seventy-one billion, eight hundred three million, eight hundred fifty-five thousand, six hundred sixty-one".