218851081 has 8 divisors (see below), whose sum is σ = 239715720. Its totient is φ = 198874368.

The previous prime is 218851069. The next prime is 218851111. The reversal of 218851081 is 180158812.

It can be written as a sum of positive squares in 4 ways, for example, as 137851081 + 81000000 = 11741^2 + 9000^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 218851081 - 2¹⁷ = 218720009 is a prime.

It is a super-2 number, since 2×218851081² = 95791591309737122, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (218851021) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 221466 + ... + 222451.

It is an arithmetic number, because the mean of its divisors is an integer number (29964465).

Almost surely, 2^218851081 is an apocalyptic number.

It is an amenable number.

218851081 is a deficient number, since it is larger than the sum of its proper divisors (20864639).

218851081 is a wasteful number, since it uses less digits than its factorization.

218851081 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 443963.

The product of its (nonzero) digits is 5120, while the sum is 34.

The square root of 218851081 is about 14793.6162245747. The cubic root of 218851081 is about 602.6283592154.

The spelling of 218851081 in words is "two hundred eighteen million, eight hundred fifty-one thousand, eighty-one".