66684840 has 32 divisors (see below), whose sum is σ = 200054880. Its totient is φ = 17782592.

The previous prime is 66684823. The next prime is 66684847. The reversal of 66684840 is 4848666.

It is a junction number, because it is equal to n+sod(n) for n = 66684792 and 66684801.

It is not an unprimeable number, because it can be changed into a prime (66684847) 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, 277734 + ... + 277973.

It is an arithmetic number, because the mean of its divisors is an integer number (6251715).

Almost surely, 2^66684840 is an apocalyptic number.

66684840 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

66684840 is an abundant number, since it is smaller than the sum of its proper divisors (133370040).

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

66684840 is a wasteful number, since it uses less digits than its factorization.

66684840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 555721 (or 555717 counting only the distinct ones).

The product of its (nonzero) digits is 221184, while the sum is 42.

The square root of 66684840 is about 8166.0786182843. The cubic root of 66684840 is about 405.5169743189.

The spelling of 66684840 in words is "sixty-six million, six hundred eighty-four thousand, eight hundred forty".