66420689 has 2 divisors, whose sum is σ = 66420690. Its totient is φ = 66420688.

The previous prime is 66420677. The next prime is 66420703. The reversal of 66420689 is 98602466.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 58675600 + 7745089 = 7660^2 + 2783^2 .

It is a cyclic number.

It is not a de Polignac number, because 66420689 - 2¹⁶ = 66355153 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (66423689) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33210344 + 33210345.

It is an arithmetic number, because the mean of its divisors is an integer number (33210345).

Almost surely, 2^66420689 is an apocalyptic number.

It is an amenable number.

66420689 is a deficient number, since it is larger than the sum of its proper divisors (1).

66420689 is an equidigital number, since it uses as much as digits as its factorization.

66420689 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 124416, while the sum is 41.

The square root of 66420689 is about 8149.8888949482. Note that the first 4 decimals coincide. The cubic root of 66420689 is about 404.9808231534.

The spelling of 66420689 in words is "sixty-six million, four hundred twenty thousand, six hundred eighty-nine".