1666651565665 has 8 divisors (see below), whose sum is σ = 2011957819200. Its totient is φ = 1325337292272.

The previous prime is 1666651565617. The next prime is 1666651565669. The reversal of 1666651565665 is 5665651566661.

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 1666651565665 - 2²¹ = 1666649468513 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 1666651565597 and 1666651565606.

It is not an unprimeable number, because it can be changed into a prime (1666651565669) 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, 997994115 + ... + 997995784.

It is an arithmetic number, because the mean of its divisors is an integer number (251494727400).

Almost surely, 2^{1666651565665} is an apocalyptic number.

It is an amenable number.

1666651565665 is a deficient number, since it is larger than the sum of its proper divisors (345306253535).

1666651565665 is a wasteful number, since it uses less digits than its factorization.

1666651565665 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1995990071.

The product of its digits is 174960000, while the sum is 64.

The spelling of 1666651565665 in words is "one trillion, six hundred sixty-six billion, six hundred fifty-one million, five hundred sixty-five thousand, six hundred sixty-five".