66616 has 16 divisors (see below), whose sum is σ = 136440. Its totient is φ = 30240.

The previous prime is 66601. The next prime is 66617. The reversal of 66616 is 61666.

It is a plaindrome in base 9.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66617) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (5) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 291 + ... + 466.

2⁶⁶⁶¹⁶ is an apocalyptic number.

It is an amenable number.

66616 is an abundant number, since it is smaller than the sum of its proper divisors (69824).

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

It is a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (68220).

66616 is a wasteful number, since it uses less digits than its factorization.

66616 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 774 (or 770 counting only the distinct ones).

The product of its digits is 1296, while the sum is 25.

The square root of 66616 is about 258.1007555200. The cubic root of 66616 is about 40.5377385371.

Subtracting from 66616 its reverse (61666), we obtain a triangular number (4950 = T₉₉).

The spelling of 66616 in words is "sixty-six thousand, six hundred sixteen".