6645866 has 8 divisors (see below), whose sum is σ = 10238340. Its totient is φ = 3233088.

The previous prime is 6645857. The next prime is 6645871. The reversal of 6645866 is 6685466.

It can be written as a sum of positive squares in 2 ways, for example, as 5193841 + 1452025 = 2279^2 + 1205^2 .

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

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, 44831 + ... + 44978.

Almost surely, 2^6645866 is an apocalyptic number.

6645866 is a deficient number, since it is larger than the sum of its proper divisors (3592474).

6645866 is a wasteful number, since it uses less digits than its factorization.

6645866 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 89848.

The product of its digits is 207360, while the sum is 41.

The square root of 6645866 is about 2577.9577188154. The cubic root of 6645866 is about 188.0112600770.

The spelling of 6645866 in words is "six million, six hundred forty-five thousand, eight hundred sixty-six".