643655376 has 240 divisors, whose sum is σ = 2315476800. Its totient is φ = 169682688.

The previous prime is 643655357. The next prime is 643655393. The reversal of 643655376 is 673556346.

643655376 is a `hidden beast` number, since 64 + 36 + 553 + 7 + 6 = 666.

643655376 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 274015 + ... + 276353.

It is an arithmetic number, because the mean of its divisors is an integer number (9647820).

Almost surely, 2^643655376 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 643655376, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1157738400).

643655376 is an abundant number, since it is smaller than the sum of its proper divisors (1671821424).

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

643655376 is a wasteful number, since it uses less digits than its factorization.

643655376 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2383 (or 2364 counting only the distinct ones).

The product of its digits is 1360800, while the sum is 45.

The square root of 643655376 is about 25370.3641282501. The cubic root of 643655376 is about 863.4114433021.

The spelling of 643655376 in words is "six hundred forty-three million, six hundred fifty-five thousand, three hundred seventy-six".