20217166666 has 48 divisors (see below), whose sum is σ = 33074502552. Its totient is φ = 9261056000.

The previous prime is 20217166663. The next prime is 20217166679. The reversal of 20217166666 is 66666171202.

It is a happy number.

It can be written as a sum of positive squares in 12 ways, for example, as 5079555441 + 15137611225 = 71271^2 + 123035^2 .

It is not an unprimeable number, because it can be changed into a prime (20217166663) 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 23 ways as a sum of consecutive naturals, for example, 16611690 + ... + 16612906.

Almost surely, 2^20217166666 is an apocalyptic number.

20217166666 is a deficient number, since it is larger than the sum of its proper divisors (12857335886).

20217166666 is a wasteful number, since it uses less digits than its factorization.

20217166666 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1995 (or 1978 counting only the distinct ones).

The product of its (nonzero) digits is 217728, while the sum is 43.

The spelling of 20217166666 in words is "twenty billion, two hundred seventeen million, one hundred sixty-six thousand, six hundred sixty-six".