643942260 has 144 divisors (see below), whose sum is σ = 2125979856. Its totient is φ = 156819456.

The previous prime is 643942259. The next prime is 643942283. The reversal of 643942260 is 62249346.

643942260 is a `hidden beast` number, since 6 + 4 + 394 + 2 + 260 = 666.

643942260 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 8 ways, for example, as 200165904 + 443776356 = 14148^2 + 21066^2 .

It is a Harshad number since it is a multiple of its sum of digits (36).

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, 225562 + ... + 228398.

It is an arithmetic number, because the mean of its divisors is an integer number (14763749).

Almost surely, 2^643942260 is an apocalyptic number.

643942260 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 643942260, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1062989928).

643942260 is an abundant number, since it is smaller than the sum of its proper divisors (1482037596).

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

643942260 is a wasteful number, since it uses less digits than its factorization.

643942260 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2962 (or 2957 counting only the distinct ones).

The product of its (nonzero) digits is 62208, while the sum is 36.

The square root of 643942260 is about 25376.0174180268. The cubic root of 643942260 is about 863.5397014488.

The spelling of 643942260 in words is "six hundred forty-three million, nine hundred forty-two thousand, two hundred sixty".