66656771 has 4 divisors (see below), whose sum is σ = 66772872. Its totient is φ = 66540672.

The previous prime is 66656767. The next prime is 66656791. The reversal of 66656771 is 17765666.

66656771 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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

It is a cyclic number.

It is not a de Polignac number, because 66656771 - 2² = 66656767 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (66656741) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 57185 + ... + 58338.

It is an arithmetic number, because the mean of its divisors is an integer number (16693218).

Almost surely, 2^66656771 is an apocalyptic number.

66656771 is a deficient number, since it is larger than the sum of its proper divisors (116101).

66656771 is a wasteful number, since it uses less digits than its factorization.

66656771 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 116100.

The product of its digits is 317520, while the sum is 44.

The square root of 66656771 is about 8164.3598034384. The cubic root of 66656771 is about 405.4600695643.

The spelling of 66656771 in words is "sixty-six million, six hundred fifty-six thousand, seven hundred seventy-one".