643055940 has 144 divisors (see below), whose sum is σ = 2132282880. Its totient is φ = 156165120.

The previous prime is 643055939. The next prime is 643055977. The reversal of 643055940 is 49550346.

It is a happy number.

643055940 is a `hidden beast` number, since 64 + 3 + 0 + 5 + 594 + 0 = 666.

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

It is a junction number, because it is equal to n+sod(n) for n = 643055895 and 643055904.

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, 91471 + ... + 98249.

It is an arithmetic number, because the mean of its divisors is an integer number (14807520).

Almost surely, 2^643055940 is an apocalyptic number.

643055940 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 643055940, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1066141440).

643055940 is an abundant number, since it is smaller than the sum of its proper divisors (1489226940).

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

643055940 is a wasteful number, since it uses less digits than its factorization.

643055940 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6842 (or 6837 counting only the distinct ones).

The product of its (nonzero) digits is 64800, while the sum is 36.

The square root of 643055940 is about 25358.5476713474. The cubic root of 643055940 is about 863.1433284733.

The spelling of 643055940 in words is "six hundred forty-three million, fifty-five thousand, nine hundred forty".