640763247 has 8 divisors (see below), whose sum is σ = 854478720. Its totient is φ = 427111640.

The previous prime is 640763231. The next prime is 640763251. The reversal of 640763247 is 742367046.

640763247 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 640763247 - 2⁴ = 640763231 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (640763287) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 17422 + ... + 39812.

It is an arithmetic number, because the mean of its divisors is an integer number (106809840).

Almost surely, 2^640763247 is an apocalyptic number.

640763247 is a deficient number, since it is larger than the sum of its proper divisors (213715473).

640763247 is a wasteful number, since it uses less digits than its factorization.

640763247 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 31933.

The product of its (nonzero) digits is 169344, while the sum is 39.

The square root of 640763247 is about 25313.3017798943. The cubic root of 640763247 is about 862.1163161317.

The spelling of 640763247 in words is "six hundred forty million, seven hundred sixty-three thousand, two hundred forty-seven".