1666446661 has 16 divisors (see below), whose sum is σ = 1920801600. Its totient is φ = 1429833600.

The previous prime is 1666446659. The next prime is 1666446671.

1666446661 is nontrivially palindromic in base 10.

It is not a de Polignac number, because 1666446661 - 2¹ = 1666446659 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1666446611) by changing a digit.

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 15 ways as a sum of consecutive naturals, for example, 41401 + ... + 71041.

It is an arithmetic number, because the mean of its divisors is an integer number (120050100).

Almost surely, 2^1666446661 is an apocalyptic number.

1666446661 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

1666446661 is a deficient number, since it is larger than the sum of its proper divisors (254354939).

1666446661 is a wasteful number, since it uses less digits than its factorization.

1666446661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 29940.

The product of its digits is 746496, while the sum is 46.

The square root of 1666446661 is about 40822.1344493401. The cubic root of 1666446661 is about 1185.5789300888.

The spelling of 1666446661 in words is "one billion, six hundred sixty-six million, four hundred forty-six thousand, six hundred sixty-one".