643726680 has 32 divisors (see below), whose sum is σ = 1931180400. Its totient is φ = 171660416.

The previous prime is 643726679. The next prime is 643726693. The reversal of 643726680 is 86627346.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2682075 + ... + 2682314.

Almost surely, 2^643726680 is an apocalyptic number.

643726680 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

643726680 is an abundant number, since it is smaller than the sum of its proper divisors (1287453720).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

643726680 is a wasteful number, since it uses less digits than its factorization.

643726680 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5364403 (or 5364399 counting only the distinct ones).

The product of its (nonzero) digits is 290304, while the sum is 42.

The square root of 643726680 is about 25371.7693509932. The cubic root of 643726680 is about 863.4433249677.

It can be divided in two parts, 6437266 and 80, that added together give a palindrome (6437346).

The spelling of 643726680 in words is "six hundred forty-three million, seven hundred twenty-six thousand, six hundred eighty".