66710666 has 16 divisors (see below), whose sum is σ = 109438560. Its totient is φ = 30246480.

The previous prime is 66710663. The next prime is 66710671. The reversal of 66710666 is 66601766.

It is a happy number.

It is not an unprimeable number, because it can be changed into a prime (66710663) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 5600 + ... + 12836.

It is an arithmetic number, because the mean of its divisors is an integer number (6839910).

Almost surely, 2^66710666 is an apocalyptic number.

66710666 is a deficient number, since it is larger than the sum of its proper divisors (42727894).

66710666 is a wasteful number, since it uses less digits than its factorization.

66710666 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7669.

The product of its (nonzero) digits is 54432, while the sum is 38.

The square root of 66710666 is about 8167.6597627472. The cubic root of 66710666 is about 405.5693176984.

Subtracting from 66710666 its reverse (66601766), we obtain a square (108900 = 330²).

It can be divided in two parts, 66710 and 666, that added together give a palindrome (67376).

The spelling of 66710666 in words is "sixty-six million, seven hundred ten thousand, six hundred sixty-six".