20660506666 has 8 divisors (see below), whose sum is σ = 31216970340. Its totient is φ = 10254849888.

The previous prime is 20660506663. The next prime is 20660506673. The reversal of 20660506666 is 66660506602.

It can be written as a sum of positive squares in 2 ways, for example, as 19919088225 + 741418441 = 141135^2 + 27229^2 .

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

It is not an unprimeable number, because it can be changed into a prime (20660506663) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 37701381 + ... + 37701928.

Almost surely, 2^20660506666 is an apocalyptic number.

20660506666 is a deficient number, since it is larger than the sum of its proper divisors (10556463674).

20660506666 is a wasteful number, since it uses less digits than its factorization.

20660506666 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 75403448.

The product of its (nonzero) digits is 466560, while the sum is 43.

The spelling of 20660506666 in words is "twenty billion, six hundred sixty million, five hundred six thousand, six hundred sixty-six".