640459829 has 2 divisors, whose sum is σ = 640459830. Its totient is φ = 640459828.

The previous prime is 640459823. The next prime is 640459861. The reversal of 640459829 is 928954046.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 394816900 + 245642929 = 19870^2 + 15673^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-640459829 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (640459823) 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, 320229914 + 320229915.

It is an arithmetic number, because the mean of its divisors is an integer number (320229915).

Almost surely, 2^640459829 is an apocalyptic number.

It is an amenable number.

640459829 is a deficient number, since it is larger than the sum of its proper divisors (1).

640459829 is an equidigital number, since it uses as much as digits as its factorization.

640459829 is an odious number, because the sum of its binary digits is odd.

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

The square root of 640459829 is about 25307.3078180987. The cubic root of 640459829 is about 861.9802165093.

The spelling of 640459829 in words is "six hundred forty million, four hundred fifty-nine thousand, eight hundred twenty-nine".