645998029 has 2 divisors, whose sum is σ = 645998030. Its totient is φ = 645998028.

The previous prime is 645997921. The next prime is 645998039. The reversal of 645998029 is 920899546.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 516652900 + 129345129 = 22730^2 + 11373^2 .

It is a cyclic number.

It is not a de Polignac number, because 645998029 - 2¹¹ = 645995981 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (645998039) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 322999014 + 322999015.

It is an arithmetic number, because the mean of its divisors is an integer number (322999015).

Almost surely, 2^645998029 is an apocalyptic number.

It is an amenable number.

645998029 is a deficient number, since it is larger than the sum of its proper divisors (1).

645998029 is an equidigital number, since it uses as much as digits as its factorization.

645998029 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1399680, while the sum is 52.

The square root of 645998029 is about 25416.4912802692. The cubic root of 645998029 is about 864.4576679955.

The spelling of 645998029 in words is "six hundred forty-five million, nine hundred ninety-eight thousand, twenty-nine".