66020081 has 2 divisors, whose sum is σ = 66020082. Its totient is φ = 66020080.

The previous prime is 66020077. The next prime is 66020147. The reversal of 66020081 is 18002066.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 53523856 + 12496225 = 7316^2 + 3535^2 .

It is a cyclic number.

It is not a de Polignac number, because 66020081 - 2² = 66020077 is a prime.

It is a super-2 number, since 2×66020081² = 8717302190493122, which contains 22 as substring.

It is a Sophie Germain prime.

It is a Chen prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (66020011) 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, 33010040 + 33010041.

It is an arithmetic number, because the mean of its divisors is an integer number (33010041).

Almost surely, 2^66020081 is an apocalyptic number.

It is an amenable number.

66020081 is a deficient number, since it is larger than the sum of its proper divisors (1).

66020081 is an equidigital number, since it uses as much as digits as its factorization.

66020081 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 576, while the sum is 23.

The square root of 66020081 is about 8125.2742107574. The cubic root of 66020081 is about 404.1649838359.

The spelling of 66020081 in words is "sixty-six million, twenty thousand, eighty-one".