664728469 has 2 divisors, whose sum is σ = 664728470. Its totient is φ = 664728468.

The previous prime is 664728461. The next prime is 664728481. The reversal of 664728469 is 964827466.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 478078225 + 186650244 = 21865^2 + 13662^2 .

It is a cyclic number.

It is not a de Polignac number, because 664728469 - 2³ = 664728461 is a prime.

It is a super-3 number, since 3×664728469³ (a number of 27 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (664728461) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 332364234 + 332364235.

It is an arithmetic number, because the mean of its divisors is an integer number (332364235).

Almost surely, 2^664728469 is an apocalyptic number.

It is an amenable number.

664728469 is a deficient number, since it is larger than the sum of its proper divisors (1).

664728469 is an equidigital number, since it uses as much as digits as its factorization.

664728469 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 3483648, while the sum is 52.

The square root of 664728469 is about 25782.3286186489. The cubic root of 664728469 is about 872.7330571741.

The spelling of 664728469 in words is "six hundred sixty-four million, seven hundred twenty-eight thousand, four hundred sixty-nine".