643661532613 has 8 divisors (see below), whose sum is σ = 702550334880. Its totient is φ = 584835083280.

The previous prime is 643661532589. The next prime is 643661532641. The reversal of 643661532613 is 316235166346.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 643661532613 - 2²⁵ = 643627978181 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (643661532313) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 15566643 + ... + 15607936.

It is an arithmetic number, because the mean of its divisors is an integer number (87818791860).

Almost surely, 2^643661532613 is an apocalyptic number.

It is an amenable number.

643661532613 is a deficient number, since it is larger than the sum of its proper divisors (58888802267).

643661532613 is a wasteful number, since it uses less digits than its factorization.

643661532613 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 31176467.

The product of its digits is 1399680, while the sum is 46.

Adding to 643661532613 its reverse (316235166346), we get a palindrome (959896698959).

The spelling of 643661532613 in words is "six hundred forty-three billion, six hundred sixty-one million, five hundred thirty-two thousand, six hundred thirteen".