640303253 has 2 divisors, whose sum is σ = 640303254. Its totient is φ = 640303252.

The previous prime is 640303207. The next prime is 640303271. The reversal of 640303253 is 352303046.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 525234724 + 115068529 = 22918^2 + 10727^2 .

It is a cyclic number.

It is not a de Polignac number, because 640303253 - 2¹² = 640299157 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (640303753) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 320151626 + 320151627.

It is an arithmetic number, because the mean of its divisors is an integer number (320151627).

Almost surely, 2^640303253 is an apocalyptic number.

It is an amenable number.

640303253 is a deficient number, since it is larger than the sum of its proper divisors (1).

640303253 is an equidigital number, since it uses as much as digits as its factorization.

640303253 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 6480, while the sum is 26.

The square root of 640303253 is about 25304.2141351989. The cubic root of 640303253 is about 861.9099667667.

Adding to 640303253 its reverse (352303046), we get a palindrome (992606299).

The spelling of 640303253 in words is "six hundred forty million, three hundred three thousand, two hundred fifty-three".