66646655 has 8 divisors (see below), whose sum is σ = 80059200. Its totient is φ = 53261856.

The previous prime is 66646651. The next prime is 66646667. The reversal of 66646655 is 55664666.

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 66646655 - 2² = 66646651 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66646651) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1220 + ... + 11609.

It is an arithmetic number, because the mean of its divisors is an integer number (10007400).

Almost surely, 2^66646655 is an apocalyptic number.

66646655 is a deficient number, since it is larger than the sum of its proper divisors (13412545).

66646655 is a wasteful number, since it uses less digits than its factorization.

66646655 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13873.

The product of its digits is 777600, while the sum is 44.

The square root of 66646655 is about 8163.7402579945. The cubic root of 66646655 is about 405.4395573117.

The spelling of 66646655 in words is "sixty-six million, six hundred forty-six thousand, six hundred fifty-five".