218611812 has 12 divisors (see below), whose sum is σ = 510094256. Its totient is φ = 72870600.

The previous prime is 218611801. The next prime is 218611819. The reversal of 218611812 is 218116812.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (12).

It is a super-2 number, since 2×218611812² = 95582248691846688, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 218611812.

It is not an unprimeable number, because it can be changed into a prime (218611819) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 9108814 + ... + 9108837.

Almost surely, 2^218611812 is an apocalyptic number.

It is an amenable number.

218611812 is an abundant number, since it is smaller than the sum of its proper divisors (291482444).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

218611812 is a wasteful number, since it uses less digits than its factorization.

218611812 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18217658 (or 18217656 counting only the distinct ones).

The product of its digits is 1536, while the sum is 30.

The square root of 218611812 is about 14785.5271126869. The cubic root of 218611812 is about 602.4086620836.

The spelling of 218611812 in words is "two hundred eighteen million, six hundred eleven thousand, eight hundred twelve".