643424040 has 128 divisors (see below), whose sum is σ = 2451168000. Its totient is φ = 147066624.

The previous prime is 643424039. The next prime is 643424069. The reversal of 643424040 is 40424346.

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 = 643423995 and 643424013.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 34995 + ... + 50114.

It is an arithmetic number, because the mean of its divisors is an integer number (19149750).

Almost surely, 2^643424040 is an apocalyptic number.

643424040 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

643424040 is an abundant number, since it is smaller than the sum of its proper divisors (1807743960).

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

643424040 is a wasteful number, since it uses less digits than its factorization.

643424040 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 85136 (or 85126 counting only the distinct ones).

The product of its (nonzero) digits is 9216, while the sum is 27.

The square root of 643424040 is about 25365.8045407592. The cubic root of 643424040 is about 863.3079914182.

Adding to 643424040 its reverse (40424346), we get a palindrome (683848386).

The spelling of 643424040 in words is "six hundred forty-three million, four hundred twenty-four thousand, forty".