2001666866687 has 4 divisors (see below), whose sum is σ = 2070689862120. Its totient is φ = 1932643871256.

The previous prime is 2001666866677. The next prime is 2001666866767. The reversal of 2001666866687 is 7866686661002.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 2001666866687 - 2¹⁶ = 2001666801151 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2001666866677) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 34511497673 + ... + 34511497730.

It is an arithmetic number, because the mean of its divisors is an integer number (517672465530).

Almost surely, 2^{2001666866687} is an apocalyptic number.

2001666866687 is a deficient number, since it is larger than the sum of its proper divisors (69022995433).

2001666866687 is an equidigital number, since it uses as much as digits as its factorization.

2001666866687 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 69022995432.

The product of its (nonzero) digits is 41803776, while the sum is 62.

The spelling of 2001666866687 in words is "two trillion, one billion, six hundred sixty-six million, eight hundred sixty-six thousand, six hundred eighty-seven".