645863329 has 2 divisors, whose sum is σ = 645863330. Its totient is φ = 645863328.

The previous prime is 645863291. The next prime is 645863377. The reversal of 645863329 is 923368546.

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., 573698304 + 72165025 = 23952^2 + 8495^2 .

It is a cyclic number.

It is not a de Polignac number, because 645863329 - 2⁹ = 645862817 is a prime.

It is not a weakly prime, because it can be changed into another prime (645863389) 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, 322931664 + 322931665.

It is an arithmetic number, because the mean of its divisors is an integer number (322931665).

Almost surely, 2^645863329 is an apocalyptic number.

It is an amenable number.

645863329 is a deficient number, since it is larger than the sum of its proper divisors (1).

645863329 is an equidigital number, since it uses as much as digits as its factorization.

645863329 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 933120, while the sum is 46.

The square root of 645863329 is about 25413.8412877707. The cubic root of 645863329 is about 864.3975798131.

The spelling of 645863329 in words is "six hundred forty-five million, eight hundred sixty-three thousand, three hundred twenty-nine".