818 has 4 divisors (see below), whose sum is σ = 1230. Its totient is φ = 408.

The previous prime is 811. The next prime is 821.

It can be divided in two parts, 8 and 18, that multiplied together give a square (144 = 12^{2}).

818 = 2^{2} + 3^{2} + ... + 13^{2}.

It is a happy number.

818 is nontrivially palindromic in base 10.

818 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 529 + 289 = 23^2 + 17^2 .

It is an alternating number because its digits alternate between even and odd.

818 is a strobogrammatic number because it is the same when read upside-down.

818 is an undulating number in base 10.

818 is a modest number, since divided by 18 gives 8 as remainder.

It is a Curzon number.

It is a plaindrome in base 5, base 7 and base 13.

It is a nialpdrome in base 16.

It is a junction number, because it is equal to *n*+sod(*n*) for *n* = 796 and 805.

It is not an unprimeable number, because it can be changed into a prime (811) by changing a digit.

818 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a pernicious number, because its binary representation contains a prime number (5) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 203 + ... + 206.

818 is a deficient number, since it is larger than the sum of its proper divisors (412).

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

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

The sum of its prime factors is 411.

The product of its digits is 64, while the sum is 17.

The square root of 818 is about 28.6006992922. The cubic root of 818 is about 9.3522857519.

The spelling of 818 in words is "eight hundred eighteen", and thus it is an aban number and an oban number.

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