1666686716 has 12 divisors (see below), whose sum is σ = 2917246920. Its totient is φ = 833187600.

The previous prime is 1666686701. The next prime is 1666686739. The reversal of 1666686716 is 6176866661.

It is a happy number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 12935 + ... + 59166.

It is an arithmetic number, because the mean of its divisors is an integer number (243103910).

Almost surely, 2^1666686716 is an apocalyptic number.

It is an amenable number.

1666686716 is a deficient number, since it is larger than the sum of its proper divisors (1250560204).

1666686716 is a wasteful number, since it uses less digits than its factorization.

1666686716 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 77884 (or 77882 counting only the distinct ones).

The product of its digits is 2612736, while the sum is 53.

The square root of 1666686716 is about 40825.0745988296. The cubic root of 1666686716 is about 1185.6358557003.

The spelling of 1666686716 in words is "one billion, six hundred sixty-six million, six hundred eighty-six thousand, seven hundred sixteen".