20666404642066 has 8 divisors (see below), whose sum is σ = 32823113255100. Its totient is φ = 9725366890368.

The previous prime is 20666404642031. The next prime is 20666404642097. The reversal of 20666404642066 is 66024640466602.

It can be written as a sum of positive squares in 2 ways, for example, as 20612825818225 + 53578823841 = 4540135^2 + 231471^2 .

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

It is a super-2 number, since 2×20666404642066² (a number of 27 digits) contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 303917715291 + ... + 303917715358.

Almost surely, 2^{20666404642066} is an apocalyptic number.

20666404642066 is a deficient number, since it is larger than the sum of its proper divisors (12156708613034).

20666404642066 is a wasteful number, since it uses less digits than its factorization.

20666404642066 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 607835430668.

The product of its (nonzero) digits is 11943936, while the sum is 52.

The spelling of 20666404642066 in words is "twenty trillion, six hundred sixty-six billion, four hundred four million, six hundred forty-two thousand, sixty-six".