643538416 has 20 divisors (see below), whose sum is σ = 1249473600. Its totient is φ = 321093632.

The previous prime is 643538411. The next prime is 643538437. The reversal of 643538416 is 614835346.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (643538411) by changing a digit.

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 3 ways as a sum of consecutive naturals, for example, 34321 + ... + 49648.

It is an arithmetic number, because the mean of its divisors is an integer number (62473680).

Almost surely, 2^643538416 is an apocalyptic number.

It is an amenable number.

643538416 is a deficient number, since it is larger than the sum of its proper divisors (605935184).

643538416 is a wasteful number, since it uses less digits than its factorization.

643538416 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 84456 (or 84450 counting only the distinct ones).

The product of its digits is 207360, while the sum is 40.

The square root of 643538416 is about 25368.0589718646. The cubic root of 643538416 is about 863.3591426852.

The spelling of 643538416 in words is "six hundred forty-three million, five hundred thirty-eight thousand, four hundred sixteen".