66216916 has 6 divisors (see below), whose sum is σ = 115879610. Its totient is φ = 33108456.

The previous prime is 66216901. The next prime is 66216929. The reversal of 66216916 is 61961266.

It can be written as a sum of positive squares in only one way, i.e., 34339600 + 31877316 = 5860^2 + 5646^2 .

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 8277111 + ... + 8277118.

Almost surely, 2^66216916 is an apocalyptic number.

It is an amenable number.

66216916 is a deficient number, since it is larger than the sum of its proper divisors (49662694).

66216916 is a wasteful number, since it uses less digits than its factorization.

66216916 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16554233 (or 16554231 counting only the distinct ones).

The product of its digits is 23328, while the sum is 37.

The square root of 66216916 is about 8137.3777102946. The cubic root of 66216916 is about 404.5662500487.

It can be divided in two parts, 662 and 16916, that added together give a triangular number (17578 = T₁₈₇).

The spelling of 66216916 in words is "sixty-six million, two hundred sixteen thousand, nine hundred sixteen".