1666668517 has 8 divisors (see below), whose sum is σ = 1683646272. Its totient is φ = 1649774400.

The previous prime is 1666668473. The next prime is 1666668529. The reversal of 1666668517 is 7158666661.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1666668517 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 (1666668547) 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 7 ways as a sum of consecutive naturals, for example, 19542 + ... + 60952.

It is an arithmetic number, because the mean of its divisors is an integer number (210455784).

Almost surely, 2^1666668517 is an apocalyptic number.

It is an amenable number.

1666668517 is a deficient number, since it is larger than the sum of its proper divisors (16977755).

1666668517 is a wasteful number, since it uses less digits than its factorization.

1666668517 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 41819.

The product of its digits is 2177280, while the sum is 52.

The square root of 1666668517 is about 40824.8517082426. The cubic root of 1666668517 is about 1185.6315402591.

The spelling of 1666668517 in words is "one billion, six hundred sixty-six million, six hundred sixty-eight thousand, five hundred seventeen".