66606661 has 8 divisors (see below), whose sum is σ = 74208384. Its totient is φ = 59262720.

The previous prime is 66606611. The next prime is 66606667. The reversal of 66606661 is 16660666.

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

It is not a de Polignac number, because 66606661 - 2¹¹ = 66604613 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 66606661.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66606667) 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, 63900 + ... + 64933.

It is an arithmetic number, because the mean of its divisors is an integer number (9276048).

Almost surely, 2^66606661 is an apocalyptic number.

It is an amenable number.

66606661 is a deficient number, since it is larger than the sum of its proper divisors (7601723).

66606661 is a wasteful number, since it uses less digits than its factorization.

66606661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 128891.

The product of its (nonzero) digits is 46656, while the sum is 37.

The square root of 66606661 is about 8161.2904004208. The cubic root of 66606661 is about 405.3584409913.

The spelling of 66606661 in words is "sixty-six million, six hundred six thousand, six hundred sixty-one".