2181218 has 16 divisors (see below), whose sum is σ = 3607296. Its totient is φ = 982800.

The previous prime is 2181217. The next prime is 2181227. The reversal of 2181218 is 8121812.

It is a happy number.

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

It is a junction number, because it is equal to n+sod(n) for n = 2181193 and 2181202.

It is not an unprimeable number, because it can be changed into a prime (2181217) 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 7 ways as a sum of consecutive naturals, for example, 143 + ... + 2093.

It is an arithmetic number, because the mean of its divisors is an integer number (225456).

2^2181218 is an apocalyptic number.

2181218 is a deficient number, since it is larger than the sum of its proper divisors (1426078).

2181218 is a wasteful number, since it uses less digits than its factorization.

2181218 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2009.

The product of its digits is 256, while the sum is 23.

The square root of 2181218 is about 1476.8947152726. The cubic root of 2181218 is about 129.6879696020.

The spelling of 2181218 in words is "two million, one hundred eighty-one thousand, two hundred eighteen".