643521334 has 8 divisors (see below), whose sum is σ = 971430768. Its totient is φ = 319711080.

The previous prime is 643521331. The next prime is 643521371. The reversal of 643521334 is 433125346.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a junction number, because it is equal to n+sod(n) for n = 643521296 and 643521305.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (643521331) 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, 1024402 + ... + 1025029.

It is an arithmetic number, because the mean of its divisors is an integer number (121428846).

Almost surely, 2^643521334 is an apocalyptic number.

643521334 is a deficient number, since it is larger than the sum of its proper divisors (327909434).

643521334 is a wasteful number, since it uses less digits than its factorization.

643521334 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2049590.

The product of its digits is 25920, while the sum is 31.

The square root of 643521334 is about 25367.7222864017. The cubic root of 643521334 is about 863.3515036533.

The spelling of 643521334 in words is "six hundred forty-three million, five hundred twenty-one thousand, three hundred thirty-four".