665455321 has 2 divisors, whose sum is σ = 665455322. Its totient is φ = 665455320.

The previous prime is 665455313. The next prime is 665455409. The reversal of 665455321 is 123554566.

665455321 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 487526400 + 177928921 = 22080^2 + 13339^2 .

It is a cyclic number.

It is not a de Polignac number, because 665455321 - 2³ = 665455313 is a prime.

It is not a weakly prime, because it can be changed into another prime (665455621) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 332727660 + 332727661.

It is an arithmetic number, because the mean of its divisors is an integer number (332727661).

Almost surely, 2^665455321 is an apocalyptic number.

It is an amenable number.

665455321 is a deficient number, since it is larger than the sum of its proper divisors (1).

665455321 is an equidigital number, since it uses as much as digits as its factorization.

665455321 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 108000, while the sum is 37.

The square root of 665455321 is about 25796.4207013299. The cubic root of 665455321 is about 873.0510399933.

The spelling of 665455321 in words is "six hundred sixty-five million, four hundred fifty-five thousand, three hundred twenty-one".