66212217 has 12 divisors (see below), whose sum is σ = 97864624. Its totient is φ = 43114680.

The previous prime is 66212213. The next prime is 66212227. The reversal of 66212217 is 71221266.

66212217 is a `hidden beast` number, since 6 + 621 + 22 + 17 = 666.

It is not a de Polignac number, because 66212217 - 2² = 66212213 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (66212213) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 85159 + ... + 85932.

Almost surely, 2^66212217 is an apocalyptic number.

It is an amenable number.

66212217 is a deficient number, since it is larger than the sum of its proper divisors (31652407).

66212217 is a wasteful number, since it uses less digits than its factorization.

66212217 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 171140 (or 171137 counting only the distinct ones).

The product of its digits is 2016, while the sum is 27.

The square root of 66212217 is about 8137.0889757947. The cubic root of 66212217 is about 404.5566799776.

The spelling of 66212217 in words is "sixty-six million, two hundred twelve thousand, two hundred seventeen".