640513249 has 2 divisors, whose sum is σ = 640513250. Its totient is φ = 640513248.

The previous prime is 640513243. The next prime is 640513421. The reversal of 640513249 is 942315046.

It is a happy number.

640513249 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 513838224 + 126675025 = 22668^2 + 11255^2 .

It is a cyclic number.

It is not a de Polignac number, because 640513249 - 2⁵ = 640513217 is a prime.

It is not a weakly prime, because it can be changed into another prime (640513243) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 320256624 + 320256625.

It is an arithmetic number, because the mean of its divisors is an integer number (320256625).

Almost surely, 2^640513249 is an apocalyptic number.

It is an amenable number.

640513249 is a deficient number, since it is larger than the sum of its proper divisors (1).

640513249 is an equidigital number, since it uses as much as digits as its factorization.

640513249 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 25920, while the sum is 34.

The square root of 640513249 is about 25308.3632224607. The cubic root of 640513249 is about 862.0041814279.

The spelling of 640513249 in words is "six hundred forty million, five hundred thirteen thousand, two hundred forty-nine".