1866561706 has 16 divisors (see below), whose sum is σ = 2825134344. Its totient is φ = 924873984.

The previous prime is 1866561703. The next prime is 1866561707. The reversal of 1866561706 is 6071656681.

It can be written as a sum of positive squares in 4 ways, for example, as 427042225 + 1439519481 = 20665^2 + 37941^2 .

It is not an unprimeable number, because it can be changed into a prime (1866561703) 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, 162406 + ... + 173518.

Almost surely, 2^1866561706 is an apocalyptic number.

1866561706 is a deficient number, since it is larger than the sum of its proper divisors (958572638).

1866561706 is a wasteful number, since it uses less digits than its factorization.

1866561706 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11865.

The product of its (nonzero) digits is 362880, while the sum is 46.

The square root of 1866561706 is about 43203.7232886241. The cubic root of 1866561706 is about 1231.2534220799.

The spelling of 1866561706 in words is "one billion, eight hundred sixty-six million, five hundred sixty-one thousand, seven hundred six".