1660660666 has 12 divisors (see below), whose sum is σ = 2897683578. Its totient is φ = 711711672.

The previous prime is 1660660663. The next prime is 1660660681. The reversal of 1660660666 is 6660660661.

It can be written as a sum of positive squares in only one way, i.e., 1650065641 + 10595025 = 40621^2 + 3255^2 .

It is not an unprimeable number, because it can be changed into a prime (1660660663) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 8472661 + ... + 8472856.

Almost surely, 2^1660660666 is an apocalyptic number.

1660660666 is a deficient number, since it is larger than the sum of its proper divisors (1237022912).

1660660666 is a wasteful number, since it uses less digits than its factorization.

1660660666 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16945533 (or 16945526 counting only the distinct ones).

The product of its (nonzero) digits is 279936, while the sum is 43.

The square root of 1660660666 is about 40751.2044729969. The cubic root of 1660660666 is about 1184.2052071009.

The spelling of 1660660666 in words is "one billion, six hundred sixty million, six hundred sixty thousand, six hundred sixty-six".