1666665666649 has 8 divisors (see below), whose sum is σ = 1690222215168. Its totient is φ = 1643111406720.

The previous prime is 1666665666619. The next prime is 1666665666707. The reversal of 1666665666649 is 9466665666661.

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

It is a cyclic number.

It is not a de Polignac number, because 1666665666649 - 2¹³ = 1666665658457 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1666665666619) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 922024 + ... + 2045350.

It is an arithmetic number, because the mean of its divisors is an integer number (211277776896).

Almost surely, 2^{1666665666649} is an apocalyptic number.

It is an amenable number.

1666665666649 is a deficient number, since it is larger than the sum of its proper divisors (23556548519).

1666665666649 is a wasteful number, since it uses less digits than its factorization.

1666665666649 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1144295.

The product of its digits is 1813985280, while the sum is 73.

The spelling of 1666665666649 in words is "one trillion, six hundred sixty-six billion, six hundred sixty-five million, six hundred sixty-six thousand, six hundred forty-nine".