66216217 has 8 divisors (see below), whose sum is σ = 68739840. Its totient is φ = 63716880.

The previous prime is 66216211. The next prime is 66216221. The reversal of 66216217 is 71261266.

It is a happy number.

66216217 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 66216217 - 2³ = 66216209 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (31).

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (66216211) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 418 + ... + 11515.

It is an arithmetic number, because the mean of its divisors is an integer number (8592480).

Almost surely, 2^66216217 is an apocalyptic number.

It is an amenable number.

66216217 is a deficient number, since it is larger than the sum of its proper divisors (2523623).

66216217 is a wasteful number, since it uses less digits than its factorization.

66216217 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12143.

The product of its digits is 6048, while the sum is 31.

The square root of 66216217 is about 8137.3347602271. The cubic root of 66216217 is about 404.5648264809.

The spelling of 66216217 in words is "sixty-six million, two hundred sixteen thousand, two hundred seventeen".