643561663443 has 8 divisors (see below), whose sum is σ = 903244440000. Its totient is φ = 406459997928.

The previous prime is 643561663399. The next prime is 643561663457. The reversal of 643561663443 is 344366165346.

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

It is not a de Polignac number, because 643561663443 - 2⁶ = 643561663379 is a prime.

It is a super-2 number, since 2×643561663443² (a number of 24 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (643561663483) 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, 5645277693 + ... + 5645277806.

It is an arithmetic number, because the mean of its divisors is an integer number (112905555000).

Almost surely, 2^643561663443 is an apocalyptic number.

643561663443 is a deficient number, since it is larger than the sum of its proper divisors (259682776557).

643561663443 is a wasteful number, since it uses less digits than its factorization.

643561663443 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11290555521.

The product of its digits is 11197440, while the sum is 51.

The spelling of 643561663443 in words is "six hundred forty-three billion, five hundred sixty-one million, six hundred sixty-three thousand, four hundred forty-three".