1666660506161 has 8 divisors (see below), whose sum is σ = 1905379603200. Its totient is φ = 1428097593888.

The previous prime is 1666660506157. The next prime is 1666660506281. The reversal of 1666660506161 is 1616050666661.

It is a happy number.

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

It is not a de Polignac number, because 1666660506161 - 2² = 1666660506157 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1666660506761) 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, 39023321 + ... + 39066006.

It is an arithmetic number, because the mean of its divisors is an integer number (238172450400).

Almost surely, 2^{1666660506161} is an apocalyptic number.

It is an amenable number.

1666660506161 is a deficient number, since it is larger than the sum of its proper divisors (238719097039).

1666660506161 is an equidigital number, since it uses as much as digits as its factorization.

1666660506161 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 78092383.

The product of its (nonzero) digits is 1399680, while the sum is 50.

The spelling of 1666660506161 in words is "one trillion, six hundred sixty-six billion, six hundred sixty million, five hundred six thousand, one hundred sixty-one".