1664218 has 4 divisors (see below), whose sum is σ = 2496330. Its totient is φ = 832108.

The previous prime is 1664123. The next prime is 1664227. The reversal of 1664218 is 8124661.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 8124661 = 401 ⋅20261.

It can be written as a sum of positive squares in only one way, i.e., 1630729 + 33489 = 1277^2 + 183^2 .

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 as a sum of consecutive naturals, namely, 416053 + ... + 416056.

2^1664218 is an apocalyptic number.

1664218 is a deficient number, since it is larger than the sum of its proper divisors (832112).

1664218 is an equidigital number, since it uses as much as digits as its factorization.

1664218 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 832111.

The product of its digits is 2304, while the sum is 28.

The square root of 1664218 is about 1290.0457356234. The cubic root of 1664218 is about 118.5050173833.

Adding to 1664218 its reverse (8124661), we get a palindrome (9788879).

The spelling of 1664218 in words is "one million, six hundred sixty-four thousand, two hundred eighteen".