643938120 has 256 divisors, whose sum is σ = 2582784000. Its totient is φ = 139408128.

The previous prime is 643938103. The next prime is 643938149. The reversal of 643938120 is 21839346.

643938120 is a `hidden beast` number, since 643 + 9 + 3 + 8 + 1 + 2 + 0 = 666.

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

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 141399 + ... + 145881.

It is an arithmetic number, because the mean of its divisors is an integer number (10089000).

Almost surely, 2^643938120 is an apocalyptic number.

643938120 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 643938120, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1291392000).

643938120 is an abundant number, since it is smaller than the sum of its proper divisors (1938845880).

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

643938120 is a wasteful number, since it uses less digits than its factorization.

643938120 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4529 (or 4519 counting only the distinct ones).

The product of its (nonzero) digits is 31104, while the sum is 36.

The square root of 643938120 is about 25375.9358448117. The cubic root of 643938120 is about 863.5378508367.

The spelling of 643938120 in words is "six hundred forty-three million, nine hundred thirty-eight thousand, one hundred twenty".