6645686 has 4 divisors (see below), whose sum is σ = 9968532. Its totient is φ = 3322842.

The previous prime is 6645679. The next prime is 6645697. The reversal of 6645686 is 6865466.

It is a semiprime because it is the product of two primes.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1661420 + ... + 1661423.

It is an arithmetic number, because the mean of its divisors is an integer number (2492133).

Almost surely, 2^6645686 is an apocalyptic number.

6645686 is a deficient number, since it is larger than the sum of its proper divisors (3322846).

6645686 is a wasteful number, since it uses less digits than its factorization.

6645686 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3322845.

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

The square root of 6645686 is about 2577.9228072229. The cubic root of 6645686 is about 188.0095626643.

The spelling of 6645686 in words is "six million, six hundred forty-five thousand, six hundred eighty-six".