1666560605 has 4 divisors (see below), whose sum is σ = 1999872732. Its totient is φ = 1333248480.

The previous prime is 1666560583. The next prime is 1666560619. The reversal of 1666560605 is 5060656661.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 168948004 + 1497612601 = 12998^2 + 38699^2 .

It is not a de Polignac number, because 1666560605 - 2¹⁶ = 1666495069 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

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 3 ways as a sum of consecutive naturals, for example, 166656056 + ... + 166656065.

It is an arithmetic number, because the mean of its divisors is an integer number (499968183).

Almost surely, 2^1666560605 is an apocalyptic number.

It is an amenable number.

1666560605 is a deficient number, since it is larger than the sum of its proper divisors (333312127).

1666560605 is an equidigital number, since it uses as much as digits as its factorization.

1666560605 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 333312126.

The product of its (nonzero) digits is 194400, while the sum is 41.

The square root of 1666560605 is about 40823.5300408968. The cubic root of 1666560605 is about 1185.6059509610.

The spelling of 1666560605 in words is "one billion, six hundred sixty-six million, five hundred sixty thousand, six hundred five".