1666845729 has 16 divisors (see below), whose sum is σ = 2470184640. Its totient is φ = 1110877920.

The previous prime is 1666845689. The next prime is 1666845743. The reversal of 1666845729 is 9275486661.

It is not a de Polignac number, because 1666845729 - 2⁹ = 1666845217 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1666845749) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 98749 + ... + 114389.

It is an arithmetic number, because the mean of its divisors is an integer number (154386540).

Almost surely, 2^1666845729 is an apocalyptic number.

It is an amenable number.

1666845729 is a deficient number, since it is larger than the sum of its proper divisors (803338911).

1666845729 is a wasteful number, since it uses less digits than its factorization.

1666845729 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19597 (or 19591 counting only the distinct ones).

The product of its digits is 4354560, while the sum is 54.

The square root of 1666845729 is about 40827.0220442295. The cubic root of 1666845729 is about 1185.6735603505.

The spelling of 1666845729 in words is "one billion, six hundred sixty-six million, eight hundred forty-five thousand, seven hundred twenty-nine".