6440818 has 4 divisors (see below), whose sum is σ = 9661230. Its totient is φ = 3220408.

The previous prime is 6440809. The next prime is 6440821. The reversal of 6440818 is 8180446.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 8180446 = 2 ⋅4090223.

It can be written as a sum of positive squares in only one way, i.e., 5678689 + 762129 = 2383^2 + 873^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 6440818.

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, 1610203 + ... + 1610206.

Almost surely, 2^6440818 is an apocalyptic number.

6440818 is a deficient number, since it is larger than the sum of its proper divisors (3220412).

6440818 is a wasteful number, since it uses less digits than its factorization.

6440818 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3220411.

The product of its (nonzero) digits is 6144, while the sum is 31.

The square root of 6440818 is about 2537.8766715505. The cubic root of 6440818 is about 186.0574262887.

The spelling of 6440818 in words is "six million, four hundred forty thousand, eight hundred eighteen".