6644866 has 4 divisors (see below), whose sum is σ = 9967302. Its totient is φ = 3322432.

The previous prime is 6644863. The next prime is 6644873. The reversal of 6644866 is 6684466.

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., 4498641 + 2146225 = 2121^2 + 1465^2 .

It is an Ulam number.

It is not an unprimeable number, because it can be changed into a prime (6644863) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1661215 + ... + 1661218.

Almost surely, 2^6644866 is an apocalyptic number.

6644866 is a deficient number, since it is larger than the sum of its proper divisors (3322436).

6644866 is a wasteful number, since it uses less digits than its factorization.

6644866 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3322435.

The product of its digits is 165888, while the sum is 40.

The square root of 6644866 is about 2577.7637595404. The cubic root of 6644866 is about 188.0018296185.

The spelling of 6644866 in words is "six million, six hundred forty-four thousand, eight hundred sixty-six".