66662161 has 2 divisors, whose sum is σ = 66662162. Its totient is φ = 66662160.

The previous prime is 66662149. The next prime is 66662179. The reversal of 66662161 is 16126666.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 48650625 + 18011536 = 6975^2 + 4244^2 .

It is a cyclic number.

It is not a de Polignac number, because 66662161 - 2⁷ = 66662033 is a prime.

It is not a weakly prime, because it can be changed into another prime (66662191) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33331080 + 33331081.

It is an arithmetic number, because the mean of its divisors is an integer number (33331081).

Almost surely, 2^66662161 is an apocalyptic number.

It is an amenable number.

66662161 is a deficient number, since it is larger than the sum of its proper divisors (1).

66662161 is an equidigital number, since it uses as much as digits as its factorization.

66662161 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 15552, while the sum is 34.

The square root of 66662161 is about 8164.6898900081. The cubic root of 66662161 is about 405.4709980408.

The spelling of 66662161 in words is "sixty-six million, six hundred sixty-two thousand, one hundred sixty-one".