1666985161 has 16 divisors (see below), whose sum is σ = 1734405120. Its totient is φ = 1600888320.

The previous prime is 1666985137. The next prime is 1666985183. The reversal of 1666985161 is 1615896661.

It is a cyclic number.

It is not a de Polignac number, because 1666985161 - 2¹⁷ = 1666854089 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1666985101) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 981465 + ... + 983161.

It is an arithmetic number, because the mean of its divisors is an integer number (108400320).

Almost surely, 2^1666985161 is an apocalyptic number.

It is an amenable number.

1666985161 is a deficient number, since it is larger than the sum of its proper divisors (67419959).

1666985161 is a wasteful number, since it uses less digits than its factorization.

1666985161 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2064.

The product of its digits is 466560, while the sum is 49.

The square root of 1666985161 is about 40828.7296030626. The cubic root of 1666985161 is about 1185.7066200439.

The spelling of 1666985161 in words is "one billion, six hundred sixty-six million, nine hundred eighty-five thousand, one hundred sixty-one".