643331632 has 10 divisors (see below), whose sum is σ = 1246455068. Its totient is φ = 321665808.

The previous prime is 643331627. The next prime is 643331651. The reversal of 643331632 is 236133346.

It is a happy number.

It is a junction number, because it is equal to n+sod(n) for n = 643331594 and 643331603.

It is an unprimeable number.

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 as a sum of consecutive naturals, namely, 20104098 + ... + 20104129.

Almost surely, 2^643331632 is an apocalyptic number.

It is an amenable number.

643331632 is a deficient number, since it is larger than the sum of its proper divisors (603123436).

643331632 is a wasteful number, since it uses less digits than its factorization.

643331632 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 40208235 (or 40208229 counting only the distinct ones).

The product of its digits is 23328, while the sum is 31.

The square root of 643331632 is about 25363.9829679804. The cubic root of 643331632 is about 863.2666602590.

Adding to 643331632 its reverse (236133346), we get a palindrome (879464978).

The spelling of 643331632 in words is "six hundred forty-three million, three hundred thirty-one thousand, six hundred thirty-two".