1213218 has 20 divisors (see below), whose sum is σ = 2718870. Its totient is φ = 404352.

The previous prime is 1213213. The next prime is 1213241. The reversal of 1213218 is 8123121.

It can be written as a sum of positive squares in only one way, i.e., 1034289 + 178929 = 1017^2 + 423^2 .

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a self number, because there is not a number n which added to its sum of digits gives 1213218.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1213213) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 9 ways as a sum of consecutive naturals, for example, 3583 + ... + 3906.

2^1213218 is an apocalyptic number.

1213218 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

1213218 is an abundant number, since it is smaller than the sum of its proper divisors (1505652).

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

1213218 is an equidigital number, since it uses as much as digits as its factorization.

1213218 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7503 (or 7494 counting only the distinct ones).

The product of its digits is 96, while the sum is 18.

The square root of 1213218 is about 1101.4617560315. The cubic root of 1213218 is about 106.6546058412.

Adding to 1213218 its reverse (8123121), we get a palindrome (9336339).

Subtracting 1213218 from its reverse (8123121), we obtain a triangular number (6909903 = T₃₇₁₇).

It can be divided in two parts, 1213 and 218, that added together give a triangular number (1431 = T₅₃).

The spelling of 1213218 in words is "one million, two hundred thirteen thousand, two hundred eighteen".