66612217 has 12 divisors (see below), whose sum is σ = 80161380. Its totient is φ = 55126176.

The previous prime is 66612197. The next prime is 66612223. The reversal of 66612217 is 71221666.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 14930496 + 51681721 = 3864^2 + 7189^2 .

It is not a de Polignac number, because 66612217 - 2¹¹ = 66610169 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (66612017) 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, 22018 + ... + 24859.

It is an arithmetic number, because the mean of its divisors is an integer number (6680115).

Almost surely, 2^66612217 is an apocalyptic number.

It is an amenable number.

66612217 is a deficient number, since it is larger than the sum of its proper divisors (13549163).

66612217 is a wasteful number, since it uses less digits than its factorization.

66612217 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 46920 (or 46913 counting only the distinct ones).

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

The square root of 66612217 is about 8161.6307806712. The cubic root of 66612217 is about 405.3697116803.

The spelling of 66612217 in words is "sixty-six million, six hundred twelve thousand, two hundred seventeen".