66329581 has 2 divisors, whose sum is σ = 66329582. Its totient is φ = 66329580.

The previous prime is 66329579. The next prime is 66329587. The reversal of 66329581 is 18592366.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 55636681 + 10692900 = 7459^2 + 3270^2 .

It is a cyclic number.

It is not a de Polignac number, because 66329581 - 2¹ = 66329579 is a prime.

It is a super-2 number, since 2×66329581² = 8799226631271122, which contains 22 as substring.

Together with 66329579, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (66329587) 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, 33164790 + 33164791.

It is an arithmetic number, because the mean of its divisors is an integer number (33164791).

Almost surely, 2^66329581 is an apocalyptic number.

It is an amenable number.

66329581 is a deficient number, since it is larger than the sum of its proper divisors (1).

66329581 is an equidigital number, since it uses as much as digits as its factorization.

66329581 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 77760, while the sum is 40.

The square root of 66329581 is about 8144.2974528194. The cubic root of 66329581 is about 404.7955702522.

The spelling of 66329581 in words is "sixty-six million, three hundred twenty-nine thousand, five hundred eighty-one".