1666445205 has 16 divisors (see below), whose sum is σ = 2731345344. Its totient is φ = 867093120.

The previous prime is 1666445203. The next prime is 1666445219. The reversal of 1666445205 is 5025446661.

It is not a de Polignac number, because 1666445205 - 2¹ = 1666445203 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1666445201) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1354219 + ... + 1355448.

It is an arithmetic number, because the mean of its divisors is an integer number (170709084).

Almost surely, 2^1666445205 is an apocalyptic number.

1666445205 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

1666445205 is a deficient number, since it is larger than the sum of its proper divisors (1064900139).

1666445205 is a wasteful number, since it uses less digits than its factorization.

1666445205 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2709716.

The product of its (nonzero) digits is 172800, while the sum is 39.

The square root of 1666445205 is about 40822.1166158738. The cubic root of 1666445205 is about 1185.5785848026.

The spelling of 1666445205 in words is "one billion, six hundred sixty-six million, four hundred forty-five thousand, two hundred five".