643739040 has 144 divisors (see below), whose sum is σ = 2510621568. Its totient is φ = 147138048.

The previous prime is 643739027. The next prime is 643739053. The reversal of 643739040 is 40937346.

643739040 is a `hidden beast` number, since 643 + 7 + 3 + 9 + 0 + 4 + 0 = 666.

643739040 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is an interprime number because it is at equal distance from previous prime (643739027) and next prime (643739053).

It is a tau number, because it is divible by the number of its divisors (144).

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 = 643738986 and 643739004.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 21852 + ... + 42011.

It is an arithmetic number, because the mean of its divisors is an integer number (17434872).

Almost surely, 2^643739040 is an apocalyptic number.

643739040 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

643739040 is an abundant number, since it is smaller than the sum of its proper divisors (1866882528).

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

643739040 is a wasteful number, since it uses less digits than its factorization.

643739040 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 63891 (or 63880 counting only the distinct ones).

The product of its (nonzero) digits is 54432, while the sum is 36.

The square root of 643739040 is about 25372.0129276335. The cubic root of 643739040 is about 863.4488511698.

The spelling of 643739040 in words is "six hundred forty-three million, seven hundred thirty-nine thousand, forty".