20320711666 has 4 divisors (see below), whose sum is σ = 30481067502. Its totient is φ = 10160355832.

The previous prime is 20320711661. The next prime is 20320711673. The reversal of 20320711666 is 66611702302.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 66611702302 = 2 ⋅33305851151.

It can be written as a sum of positive squares in only one way, i.e., 19760206041 + 560505625 = 140571^2 + 23675^2 .

It is a super-2 number, since 2×20320711666² (a number of 21 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (20320711661) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5080177915 + ... + 5080177918.

Almost surely, 2^20320711666 is an apocalyptic number.

20320711666 is a deficient number, since it is larger than the sum of its proper divisors (10160355836).

20320711666 is a wasteful number, since it uses less digits than its factorization.

20320711666 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10160355835.

The product of its (nonzero) digits is 18144, while the sum is 34.

The spelling of 20320711666 in words is "twenty billion, three hundred twenty million, seven hundred eleven thousand, six hundred sixty-six".