212818 has 8 divisors (see below), whose sum is σ = 322812. Its totient is φ = 105216.

The previous prime is 212801. The next prime is 212827. The reversal of 212818 is 818212.

It can be written as a sum of positive squares in 2 ways, for example, as 208849 + 3969 = 457^2 + 63^2 .

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

It is a super-2 number, since 2×212818² = 90583002248, which contains 22 as substring.

It is an Ulam number.

It is an unprimeable number.

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, 355 + ... + 742.

2²¹²⁸¹⁸ is an apocalyptic number.

212818 is a deficient number, since it is larger than the sum of its proper divisors (109994).

212818 is a wasteful number, since it uses less digits than its factorization.

212818 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1196.

The product of its digits is 256, while the sum is 22.

The square root of 212818 is about 461.3220133486. The cubic root of 212818 is about 59.7039116352.

The spelling of 212818 in words is "two hundred twelve thousand, eight hundred eighteen".