66688766 has 4 divisors (see below), whose sum is σ = 100033152. Its totient is φ = 33344382.

The previous prime is 66688759. The next prime is 66688789. The reversal of 66688766 is 66788666.

It is a semiprime because it is the product of two primes.

It is a congruent number.

It is an unprimeable number.

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 as a sum of consecutive naturals, namely, 16672190 + ... + 16672193.

It is an arithmetic number, because the mean of its divisors is an integer number (25008288).

Almost surely, 2^66688766 is an apocalyptic number.

66688766 is a deficient number, since it is larger than the sum of its proper divisors (33344386).

66688766 is a wasteful number, since it uses less digits than its factorization.

66688766 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 33344385.

The product of its digits is 3483648, while the sum is 53.

The square root of 66688766 is about 8166.3189994024. The cubic root of 66688766 is about 405.5249322915.

The spelling of 66688766 in words is "sixty-six million, six hundred eighty-eight thousand, seven hundred sixty-six".