66959989 has 2 divisors, whose sum is σ = 66959990. Its totient is φ = 66959988.

The previous prime is 66959953. The next prime is 66960017. The reversal of 66959989 is 98995966.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 66699889 + 260100 = 8167^2 + 510^2 .

It is a cyclic number.

It is not a de Polignac number, because 66959989 - 2¹⁷ = 66828917 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (66969989) 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, 33479994 + 33479995.

It is an arithmetic number, because the mean of its divisors is an integer number (33479995).

Almost surely, 2^66959989 is an apocalyptic number.

It is an amenable number.

66959989 is a deficient number, since it is larger than the sum of its proper divisors (1).

66959989 is an equidigital number, since it uses as much as digits as its factorization.

66959989 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 9447840, while the sum is 61.

The square root of 66959989 is about 8182.9083460589. The cubic root of 66959989 is about 406.0739448902.

The spelling of 66959989 in words is "sixty-six million, nine hundred fifty-nine thousand, nine hundred eighty-nine".