66471389 has 2 divisors, whose sum is σ = 66471390. Its totient is φ = 66471388.

The previous prime is 66471371. The next prime is 66471467. The reversal of 66471389 is 98317466.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 44662489 + 21808900 = 6683^2 + 4670^2 .

It is a cyclic number.

It is not a de Polignac number, because 66471389 - 2⁸ = 66471133 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (66471589) 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, 33235694 + 33235695.

It is an arithmetic number, because the mean of its divisors is an integer number (33235695).

Almost surely, 2^66471389 is an apocalyptic number.

It is an amenable number.

66471389 is a deficient number, since it is larger than the sum of its proper divisors (1).

66471389 is an equidigital number, since it uses as much as digits as its factorization.

66471389 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 217728, while the sum is 44.

The square root of 66471389 is about 8152.9987734575. The cubic root of 66471389 is about 405.0838397786.

The spelling of 66471389 in words is "sixty-six million, four hundred seventy-one thousand, three hundred eighty-nine".