2066855661 has 12 divisors (see below), whose sum is σ = 3215108988. Its totient is φ = 1271911104.

The previous prime is 2066855639. The next prime is 2066855683. The reversal of 2066855661 is 1665586602.

It is a happy number.

2066855661 is a `hidden beast` number, since 2 + 0 + 6 + 6 + 85 + 566 + 1 = 666.

It is an interprime number because it is at equal distance from previous prime (2066855639) and next prime (2066855683).

It can be written as a sum of positive squares in 2 ways, for example, as 521894025 + 1544961636 = 22845^2 + 39306^2 .

It is not a de Polignac number, because 2066855661 - 2⁵ = 2066855629 is a prime.

It is a Smith number, since the sum of its digits (45) coincides with the sum of the digits of its prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2066855621) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 8832600 + ... + 8832833.

It is an arithmetic number, because the mean of its divisors is an integer number (267925749).

Almost surely, 2^2066855661 is an apocalyptic number.

It is an amenable number.

2066855661 is a deficient number, since it is larger than the sum of its proper divisors (1148253327).

2066855661 is a wasteful number, since it uses less digits than its factorization.

2066855661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17665452 (or 17665449 counting only the distinct ones).

The product of its (nonzero) digits is 518400, while the sum is 45.

The square root of 2066855661 is about 45462.6842696293. The cubic root of 2066855661 is about 1273.8062718701.

The spelling of 2066855661 in words is "two billion, sixty-six million, eight hundred fifty-five thousand, six hundred sixty-one".