643032561 has 16 divisors (see below), whose sum is σ = 924517440. Its totient is φ = 396218880.

The previous prime is 643032557. The next prime is 643032581. The reversal of 643032561 is 165230346.

It is not a de Polignac number, because 643032561 - 2² = 643032557 is a prime.

It is not an unprimeable number, because it can be changed into a prime (643032581) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 135240 + ... + 139913.

It is an arithmetic number, because the mean of its divisors is an integer number (57782340).

Almost surely, 2^643032561 is an apocalyptic number.

It is an amenable number.

643032561 is a deficient number, since it is larger than the sum of its proper divisors (281484879).

643032561 is a wasteful number, since it uses less digits than its factorization.

643032561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 275216.

The product of its (nonzero) digits is 12960, while the sum is 30.

The square root of 643032561 is about 25358.0866983296. The cubic root of 643032561 is about 863.1328681741.

The spelling of 643032561 in words is "six hundred forty-three million, thirty-two thousand, five hundred sixty-one".