640563247 has 16 divisors (see below), whose sum is σ = 700578720. Its totient is φ = 583345152.

The previous prime is 640563239. The next prime is 640563251. The reversal of 640563247 is 742365046.

640563247 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a cyclic number.

It is not a de Polignac number, because 640563247 - 2³ = 640563239 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (640563227) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 60904 + ... + 70642.

It is an arithmetic number, because the mean of its divisors is an integer number (43786170).

Almost surely, 2^640563247 is an apocalyptic number.

640563247 is a deficient number, since it is larger than the sum of its proper divisors (60015473).

640563247 is a wasteful number, since it uses less digits than its factorization.

640563247 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9882.

The product of its (nonzero) digits is 120960, while the sum is 37.

The square root of 640563247 is about 25309.3509794305. The cubic root of 640563247 is about 862.0266099849.

The spelling of 640563247 in words is "six hundred forty million, five hundred sixty-three thousand, two hundred forty-seven".