66688216 has 24 divisors (see below), whose sum is σ = 145456020. Its totient is φ = 28580496.

The previous prime is 66688211. The next prime is 66688217. The reversal of 66688216 is 61288666.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66688211) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 84670 + ... + 85453.

Almost surely, 2^66688216 is an apocalyptic number.

It is an amenable number.

66688216 is an abundant number, since it is smaller than the sum of its proper divisors (78767804).

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

66688216 is a wasteful number, since it uses less digits than its factorization.

66688216 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 170143 (or 170132 counting only the distinct ones).

The product of its digits is 165888, while the sum is 43.

The square root of 66688216 is about 8166.2853244300. The cubic root of 66688216 is about 405.5238174644.

It can be divided in two parts, 6668 and 8216, that added together give a square (14884 = 122²).

The spelling of 66688216 in words is "sixty-six million, six hundred eighty-eight thousand, two hundred sixteen".