643556334 has 32 divisors (see below), whose sum is σ = 1359550080. Its totient is φ = 202524192.

The previous prime is 643556327. The next prime is 643556339. The reversal of 643556334 is 433655346.

It is a junction number, because it is equal to n+sod(n) for n = 643556292 and 643556301.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (643556339) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 23769 + ... + 43035.

It is an arithmetic number, because the mean of its divisors is an integer number (42485940).

Almost surely, 2^643556334 is an apocalyptic number.

643556334 is an abundant number, since it is smaller than the sum of its proper divisors (715993746).

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

643556334 is a wasteful number, since it uses less digits than its factorization.

643556334 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 19584.

The product of its digits is 388800, while the sum is 39.

The square root of 643556334 is about 25368.4121300487. The cubic root of 643556334 is about 863.3671554291.

The spelling of 643556334 in words is "six hundred forty-three million, five hundred fifty-six thousand, three hundred thirty-four".