66064381 has 2 divisors, whose sum is σ = 66064382. Its totient is φ = 66064380.

The previous prime is 66064367. The next prime is 66064393. The reversal of 66064381 is 18346066.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 60140025 + 5924356 = 7755^2 + 2434^2 .

It is a cyclic number.

It is not a de Polignac number, because 66064381 - 2¹³ = 66056189 is a prime.

It is a super-2 number, since 2×66064381² = 8729004873826322, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (66064321) 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, 33032190 + 33032191.

It is an arithmetic number, because the mean of its divisors is an integer number (33032191).

Almost surely, 2^66064381 is an apocalyptic number.

It is an amenable number.

66064381 is a deficient number, since it is larger than the sum of its proper divisors (1).

66064381 is an equidigital number, since it uses as much as digits as its factorization.

66064381 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 20736, while the sum is 34.

The square root of 66064381 is about 8127.9998154528. Note that the first 3 decimals coincide. The cubic root of 66064381 is about 404.2553629312.

The spelling of 66064381 in words is "sixty-six million, sixty-four thousand, three hundred eighty-one".