66666687 has 8 divisors (see below), whose sum is σ = 93567360. Its totient is φ = 42105240.

The previous prime is 66666683. The next prime is 66666713. The reversal of 66666687 is 78666666.

It is a happy number.

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

It is not a de Polignac number, because 66666687 - 2² = 66666683 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66666683) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 584739 + ... + 584852.

It is an arithmetic number, because the mean of its divisors is an integer number (11695920).

Almost surely, 2^66666687 is an apocalyptic number.

66666687 is a deficient number, since it is larger than the sum of its proper divisors (26900673).

66666687 is a wasteful number, since it uses less digits than its factorization.

66666687 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1169613.

The product of its digits is 2612736, while the sum is 51.

The square root of 66666687 is about 8164.9670544345. The cubic root of 66666687 is about 405.4801742620.

The spelling of 66666687 in words is "sixty-six million, six hundred sixty-six thousand, six hundred eighty-seven".