6640655 has 8 divisors (see below), whose sum is σ = 9107232. Its totient is φ = 4553568.

The previous prime is 6640651. The next prime is 6640657. The reversal of 6640655 is 5560466.

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

It is a cyclic number.

It is not a de Polignac number, because 6640655 - 2² = 6640651 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6640651) by changing a digit.

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 7 ways as a sum of consecutive naturals, for example, 94832 + ... + 94901.

It is an arithmetic number, because the mean of its divisors is an integer number (1138404).

Almost surely, 2^6640655 is an apocalyptic number.

6640655 is a deficient number, since it is larger than the sum of its proper divisors (2466577).

6640655 is a wasteful number, since it uses less digits than its factorization.

6640655 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 189745.

The product of its (nonzero) digits is 21600, while the sum is 32.

The square root of 6640655 is about 2576.9468368595. The cubic root of 6640655 is about 187.9621075736.

The spelling of 6640655 in words is "six million, six hundred forty thousand, six hundred fifty-five".