665641829 has 2 divisors, whose sum is σ = 665641830. Its totient is φ = 665641828.

The previous prime is 665641819. The next prime is 665641883. The reversal of 665641829 is 928146566.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 664453729 + 1188100 = 25777^2 + 1090^2 .

It is a cyclic number.

It is not a de Polignac number, because 665641829 - 2²⁰ = 664593253 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (665641819) 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, 332820914 + 332820915.

It is an arithmetic number, because the mean of its divisors is an integer number (332820915).

Almost surely, 2^665641829 is an apocalyptic number.

It is an amenable number.

665641829 is a deficient number, since it is larger than the sum of its proper divisors (1).

665641829 is an equidigital number, since it uses as much as digits as its factorization.

665641829 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 622080, while the sum is 47.

The square root of 665641829 is about 25800.0354457121. The cubic root of 665641829 is about 873.1325960789.

The spelling of 665641829 in words is "six hundred sixty-five million, six hundred forty-one thousand, eight hundred twenty-nine".