218818361 has 4 divisors (see below), whose sum is σ = 218847972. Its totient is φ = 218788752.

The previous prime is 218818349. The next prime is 218818363. The reversal of 218818361 is 163818812.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in 2 ways, for example, as 206784400 + 12033961 = 14380^2 + 3469^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-218818361 is a prime.

It is a super-2 number, since 2×218818361² = 95762950221452642, which contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (218818363) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 6491 + ... + 21903.

It is an arithmetic number, because the mean of its divisors is an integer number (54711993).

Almost surely, 2^218818361 is an apocalyptic number.

It is an amenable number.

218818361 is a deficient number, since it is larger than the sum of its proper divisors (29611).

218818361 is a wasteful number, since it uses less digits than its factorization.

218818361 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 29610.

The product of its digits is 18432, while the sum is 38.

The square root of 218818361 is about 14792.5103008245. The cubic root of 218818361 is about 602.5983251202.

The spelling of 218818361 in words is "two hundred eighteen million, eight hundred eighteen thousand, three hundred sixty-one".