643181040 has 160 divisors (see below), whose sum is σ = 2228428800. Its totient is φ = 170507520.

The previous prime is 643180991. The next prime is 643181047. The reversal of 643181040 is 40181346.

643181040 is a `hidden beast` number, since 643 + 1 + 8 + 10 + 4 + 0 = 666.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a junction number, because it is equal to n+sod(n) for n = 643180995 and 643181013.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (643181047) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 411781 + ... + 413339.

It is an arithmetic number, because the mean of its divisors is an integer number (13927680).

Almost surely, 2^643181040 is an apocalyptic number.

643181040 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 643181040, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1114214400).

643181040 is an abundant number, since it is smaller than the sum of its proper divisors (1585247760).

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

643181040 is a wasteful number, since it uses less digits than its factorization.

643181040 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1772 (or 1760 counting only the distinct ones).

The product of its (nonzero) digits is 2304, while the sum is 27.

The square root of 643181040 is about 25361.0141753046. The cubic root of 643181040 is about 863.1992967659.

The spelling of 643181040 in words is "six hundred forty-three million, one hundred eighty-one thousand, forty".