643257863 has 4 divisors (see below), whose sum is σ = 677113560. Its totient is φ = 609402168.

The previous prime is 643257851. The next prime is 643257869. The reversal of 643257863 is 368752346.

643257863 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 643257863 - 2⁴ = 643257847 is a prime.

It is a super-2 number, since 2×643257863² = 827561356622653538, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (643257869) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 16927820 + ... + 16927857.

It is an arithmetic number, because the mean of its divisors is an integer number (169278390).

Almost surely, 2^643257863 is an apocalyptic number.

643257863 is a deficient number, since it is larger than the sum of its proper divisors (33855697).

643257863 is a wasteful number, since it uses less digits than its factorization.

643257863 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 33855696.

The product of its digits is 725760, while the sum is 44.

The square root of 643257863 is about 25362.5287185643. The cubic root of 643257863 is about 863.2336628906.

The spelling of 643257863 in words is "six hundred forty-three million, two hundred fifty-seven thousand, eight hundred sixty-three".