643091916 has 24 divisors (see below), whose sum is σ = 1519544320. Its totient is φ = 211650192.

The previous prime is 643091903. The next prime is 643091921. The reversal of 643091916 is 619190346.

643091916 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 338236 + ... + 340131.

Almost surely, 2^643091916 is an apocalyptic number.

It is an amenable number.

643091916 is an abundant number, since it is smaller than the sum of its proper divisors (876452404).

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

643091916 is a wasteful number, since it uses less digits than its factorization.

643091916 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 678453 (or 678451 counting only the distinct ones).

The product of its (nonzero) digits is 34992, while the sum is 39.

The square root of 643091916 is about 25359.2570080434. The cubic root of 643091916 is about 863.1594244629.

It can be divided in two parts, 6430 and 91916, that added together give a triangular number (98346 = T₄₄₃).

The spelling of 643091916 in words is "six hundred forty-three million, ninety-one thousand, nine hundred sixteen".