691666666 has 8 divisors (see below), whose sum is σ = 1037645280. Its totient is φ = 345784908.

The previous prime is 691666663. The next prime is 691666673. The reversal of 691666666 is 666666196.

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

691666666 is a modest number, since divided by 66666 gives 6916 as remainder.

It is not an unprimeable number, because it can be changed into a prime (691666663) 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 3 ways as a sum of consecutive naturals, for example, 2446 + ... + 37273.

It is an arithmetic number, because the mean of its divisors is an integer number (129705660).

Almost surely, 2^691666666 is an apocalyptic number.

691666666 is a deficient number, since it is larger than the sum of its proper divisors (345978614).

691666666 is a wasteful number, since it uses less digits than its factorization.

691666666 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 48428.

The product of its digits is 2519424, while the sum is 52.

The square root of 691666666 is about 26299.5563840913. The cubic root of 691666666 is about 884.3664978077.

The spelling of 691666666 in words is "six hundred ninety-one million, six hundred sixty-six thousand, six hundred sixty-six".