643765632 has 32 divisors (see below), whose sum is σ = 1710003480. Its totient is φ = 214588416.

The previous prime is 643765631. The next prime is 643765637. The reversal of 643765632 is 236567346.

It is a tau number, because it is divible by the number of its divisors (32).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (643765631) 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 3 ways as a sum of consecutive naturals, for example, 837853 + ... + 838620.

Almost surely, 2^643765632 is an apocalyptic number.

It is an amenable number.

643765632 is an abundant number, since it is smaller than the sum of its proper divisors (1066237848).

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

643765632 is a wasteful number, since it uses less digits than its factorization.

643765632 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1676490 (or 1676478 counting only the distinct ones).

The product of its digits is 544320, while the sum is 42.

The square root of 643765632 is about 25372.5369642060. The cubic root of 643765632 is about 863.4607403123.

The spelling of 643765632 in words is "six hundred forty-three million, seven hundred sixty-five thousand, six hundred thirty-two".