665166571 has 2 divisors, whose sum is σ = 665166572. Its totient is φ = 665166570.

The previous prime is 665166529. The next prime is 665166577. The reversal of 665166571 is 175661566.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 665166571 - 2¹¹ = 665164523 is a prime.

It is not a weakly prime, because it can be changed into another prime (665166577) 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, 332583285 + 332583286.

It is an arithmetic number, because the mean of its divisors is an integer number (332583286).

Almost surely, 2^665166571 is an apocalyptic number.

665166571 is a deficient number, since it is larger than the sum of its proper divisors (1).

665166571 is an equidigital number, since it uses as much as digits as its factorization.

665166571 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 226800, while the sum is 43.

The square root of 665166571 is about 25790.8233873989. The cubic root of 665166571 is about 872.9247455345.

The spelling of 665166571 in words is "six hundred sixty-five million, one hundred sixty-six thousand, five hundred seventy-one".