1981218 has 8 divisors (see below), whose sum is σ = 3962448. Its totient is φ = 660404.

The previous prime is 1981201. The next prime is 1981237. The reversal of 1981218 is 8121891.

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

1981218 is an admirable number.

It is a super-3 number, since 3×1981218³ = 23330177866618476696, which contains 333 as substring.

It is a Curzon number.

It is a plaindrome in base 11.

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, 165096 + ... + 165107.

It is an arithmetic number, because the mean of its divisors is an integer number (495306).

2^1981218 is an apocalyptic number.

1981218 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

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

1981218 is a wasteful number, since it uses less digits than its factorization.

1981218 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 330208.

The product of its digits is 1152, while the sum is 30.

The square root of 1981218 is about 1407.5574588627. The cubic root of 1981218 is about 125.5964666268.

The spelling of 1981218 in words is "one million, nine hundred eighty-one thousand, two hundred eighteen".