643506967 has 4 divisors (see below), whose sum is σ = 681360336. Its totient is φ = 605653600.

The previous prime is 643506961. The next prime is 643506971. The reversal of 643506967 is 769605346.

643506967 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 643506967 - 2¹¹ = 643504919 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 (643506961) 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, 18926659 + ... + 18926692.

It is an arithmetic number, because the mean of its divisors is an integer number (170340084).

Almost surely, 2^643506967 is an apocalyptic number.

643506967 is a deficient number, since it is larger than the sum of its proper divisors (37853369).

643506967 is a wasteful number, since it uses less digits than its factorization.

643506967 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 37853368.

The product of its (nonzero) digits is 816480, while the sum is 46.

The square root of 643506967 is about 25367.4391100087. The cubic root of 643506967 is about 863.3450786587.

It can be divided in two parts, 64350 and 6967, that added together give a palindrome (71317).

The spelling of 643506967 in words is "six hundred forty-three million, five hundred six thousand, nine hundred sixty-seven".