66420161 has 2 divisors, whose sum is σ = 66420162. Its totient is φ = 66420160.

The previous prime is 66420149. The next prime is 66420163. The reversal of 66420161 is 16102466.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 65529025 + 891136 = 8095^2 + 944^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-66420161 is a prime.

Together with 66420163, it forms a pair of twin primes.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 66420161.

It is not a weakly prime, because it can be changed into another prime (66420163) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33210080 + 33210081.

It is an arithmetic number, because the mean of its divisors is an integer number (33210081).

Almost surely, 2^66420161 is an apocalyptic number.

It is an amenable number.

66420161 is a deficient number, since it is larger than the sum of its proper divisors (1).

66420161 is an equidigital number, since it uses as much as digits as its factorization.

66420161 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1728, while the sum is 26.

The square root of 66420161 is about 8149.8565018042. The cubic root of 66420161 is about 404.9797500417.

The spelling of 66420161 in words is "sixty-six million, four hundred twenty thousand, one hundred sixty-one".