1640218 has 4 divisors (see below), whose sum is σ = 2460330. Its totient is φ = 820108.

The previous prime is 1640207. The next prime is 1640231. The reversal of 1640218 is 8120461.

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., 1505529 + 134689 = 1227^2 + 367^2 .

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 an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 410053 + ... + 410056.

2^1640218 is an apocalyptic number.

1640218 is a deficient number, since it is larger than the sum of its proper divisors (820112).

1640218 is an equidigital number, since it uses as much as digits as its factorization.

1640218 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 820111.

The product of its (nonzero) digits is 384, while the sum is 22.

The square root of 1640218 is about 1280.7099593585. The cubic root of 1640218 is about 117.9325958051.

Adding to 1640218 its reverse (8120461), we get a palindrome (9760679).

The spelling of 1640218 in words is "one million, six hundred forty thousand, two hundred eighteen".