1666065666511 has 4 divisors (see below), whose sum is σ = 1666575014224. Its totient is φ = 1665556318800.

The previous prime is 1666065666491. The next prime is 1666065666533. The reversal of 1666065666511 is 1156665606661.

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 1666065666511 - 2¹³ = 1666065658319 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 (1666065666541) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 254668950 + ... + 254675491.

It is an arithmetic number, because the mean of its divisors is an integer number (416643753556).

Almost surely, 2^{1666065666511} is an apocalyptic number.

1666065666511 is a deficient number, since it is larger than the sum of its proper divisors (509347713).

1666065666511 is an equidigital number, since it uses as much as digits as its factorization.

1666065666511 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 509347712.

The product of its (nonzero) digits is 6998400, while the sum is 55.

The spelling of 1666065666511 in words is "one trillion, six hundred sixty-six billion, sixty-five million, six hundred sixty-six thousand, five hundred eleven".