66688680 has 32 divisors (see below), whose sum is σ = 200066400. Its totient is φ = 17783616.

The previous prime is 66688669. The next prime is 66688691. The reversal of 66688680 is 8688666.

It is an interprime number because it is at equal distance from previous prime (66688669) and next prime (66688691).

It is a Smith number, since the sum of its digits (48) coincides with the sum of the digits of its prime factors.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 277750 + ... + 277989.

It is an arithmetic number, because the mean of its divisors is an integer number (6252075).

Almost surely, 2^66688680 is an apocalyptic number.

66688680 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

66688680 is an abundant number, since it is smaller than the sum of its proper divisors (133377720).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

66688680 is a wasteful number, since it uses less digits than its factorization.

66688680 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 555753 (or 555749 counting only the distinct ones).

The product of its (nonzero) digits is 663552, while the sum is 48.

The square root of 66688680 is about 8166.3137338704. The cubic root of 66688680 is about 405.5247579735.

The spelling of 66688680 in words is "sixty-six million, six hundred eighty-eight thousand, six hundred eighty".