66171389 has 2 divisors, whose sum is σ = 66171390. Its totient is φ = 66171388.

The previous prime is 66171373. The next prime is 66171407. The reversal of 66171389 is 98317166.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 55995289 + 10176100 = 7483^2 + 3190^2 .

It is a cyclic number.

It is not a de Polignac number, because 66171389 - 2⁴ = 66171373 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 (66171349) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33085694 + 33085695.

It is an arithmetic number, because the mean of its divisors is an integer number (33085695).

Almost surely, 2^66171389 is an apocalyptic number.

It is an amenable number.

66171389 is a deficient number, since it is larger than the sum of its proper divisors (1).

66171389 is an equidigital number, since it uses as much as digits as its factorization.

66171389 is an evil number, because the sum of its binary digits is even.

The product of its digits is 54432, while the sum is 41.

The square root of 66171389 is about 8134.5798293458. The cubic root of 66171389 is about 404.4735098467.

The spelling of 66171389 in words is "sixty-six million, one hundred seventy-one thousand, three hundred eighty-nine".