643641432 has 32 divisors (see below), whose sum is σ = 1838976000. Its totient is φ = 183897504.

The previous prime is 643641431. The next prime is 643641433. The reversal of 643641432 is 234146346.

It is an interprime number because it is at equal distance from previous prime (643641431) and next prime (643641433).

It is a nude number because it is divisible by every one of its digits.

It is a junction number, because it is equal to n+sod(n) for n = 643641393 and 643641402.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (643641431) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1915432 + ... + 1915767.

It is an arithmetic number, because the mean of its divisors is an integer number (57468000).

Almost surely, 2^643641432 is an apocalyptic number.

It is an amenable number.

643641432 is an abundant number, since it is smaller than the sum of its proper divisors (1195334568).

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

643641432 is a wasteful number, since it uses less digits than its factorization.

643641432 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3831215 (or 3831211 counting only the distinct ones).

The product of its digits is 41472, while the sum is 33.

The square root of 643641432 is about 25370.0893179350. The cubic root of 643641432 is about 863.4052083423.

Adding to 643641432 its reverse (234146346), we get a palindrome (877787778).

The spelling of 643641432 in words is "six hundred forty-three million, six hundred forty-one thousand, four hundred thirty-two".