643361056 has 96 divisors (see below), whose sum is σ = 1494566640. Its totient is φ = 269746176.

The previous prime is 643361009. The next prime is 643361057. The reversal of 643361056 is 650163346.

It can be written as a sum of positive squares in 8 ways, for example, as 523677456 + 119683600 = 22884^2 + 10940^2 .

It is a Harshad number since it is a multiple of its sum of digits (34).

It is not an unprimeable number, because it can be changed into a prime (643361057) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 203520 + ... + 206656.

Almost surely, 2^643361056 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 643361056, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (747283320).

643361056 is an abundant number, since it is smaller than the sum of its proper divisors (851205584).

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

643361056 is a wasteful number, since it uses less digits than its factorization.

643361056 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3206 (or 3198 counting only the distinct ones).

The product of its (nonzero) digits is 38880, while the sum is 34.

The square root of 643361056 is about 25364.5629964326. The cubic root of 643361056 is about 863.2798211077.

The spelling of 643361056 in words is "six hundred forty-three million, three hundred sixty-one thousand, fifty-six".