1666116661 has 8 divisors (see below), whose sum is σ = 1817890848. Its totient is φ = 1514394000.

The previous prime is 1666116587. The next prime is 1666116679.

1666116661 is nontrivially palindromic in base 10.

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 1666116661 - 2¹³ = 1666108469 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 (1666116691) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 91671 + ... + 108331.

It is an arithmetic number, because the mean of its divisors is an integer number (227236356).

Almost surely, 2^1666116661 is an apocalyptic number.

1666116661 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

1666116661 is a deficient number, since it is larger than the sum of its proper divisors (151774187).

1666116661 is a wasteful number, since it uses less digits than its factorization.

1666116661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 25763.

The product of its digits is 46656, while the sum is 40.

The square root of 1666116661 is about 40818.0923243603. The cubic root of 1666116661 is about 1185.5006663827.

The spelling of 1666116661 in words is "one billion, six hundred sixty-six million, one hundred sixteen thousand, six hundred sixty-one".