1820218 has 4 divisors (see below), whose sum is σ = 2730330. Its totient is φ = 910108.

The previous prime is 1820213. The next prime is 1820237. The reversal of 1820218 is 8120281.

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., 1361889 + 458329 = 1167^2 + 677^2 .

It is a Smith number, since the sum of its digits (22) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is not an unprimeable number, because it can be changed into a prime (1820213) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 455053 + ... + 455056.

2^1820218 is an apocalyptic number.

1820218 is a deficient number, since it is larger than the sum of its proper divisors (910112).

1820218 is an equidigital number, since it uses as much as digits as its factorization.

1820218 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 910111.

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

The square root of 1820218 is about 1349.1545500794. The cubic root of 1820218 is about 122.0977895521.

Adding to 1820218 its reverse (8120281), we get a palindrome (9940499).

The spelling of 1820218 in words is "one million, eight hundred twenty thousand, two hundred eighteen".