1666835217 has 12 divisors (see below), whose sum is σ = 2412683520. Its totient is φ = 1108900728.

The previous prime is 1666835201. The next prime is 1666835239. The reversal of 1666835217 is 7125386661.

It is not a de Polignac number, because 1666835217 - 2⁴ = 1666835201 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1666835257) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 189013 + ... + 197634.

It is an arithmetic number, because the mean of its divisors is an integer number (201056960).

Almost surely, 2^1666835217 is an apocalyptic number.

It is an amenable number.

1666835217 is a deficient number, since it is larger than the sum of its proper divisors (745848303).

1666835217 is a wasteful number, since it uses less digits than its factorization.

1666835217 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 387132 (or 387129 counting only the distinct ones).

The product of its digits is 362880, while the sum is 45.

The square root of 1666835217 is about 40826.8933057611. The cubic root of 1666835217 is about 1185.6710678529.

The spelling of 1666835217 in words is "one billion, six hundred sixty-six million, eight hundred thirty-five thousand, two hundred seventeen".