643826721211 has 8 divisors (see below), whose sum is σ = 646556663984. Its totient is φ = 641097262080.

The previous prime is 643826721199. The next prime is 643826721217. The reversal of 643826721211 is 112127628346.

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 643826721211 - 2¹¹ = 643826719163 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (643826721217) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2684716 + ... + 2914678.

It is an arithmetic number, because the mean of its divisors is an integer number (80819582998).

Almost surely, 2^643826721211 is an apocalyptic number.

643826721211 is a deficient number, since it is larger than the sum of its proper divisors (2729942773).

643826721211 is a wasteful number, since it uses less digits than its factorization.

643826721211 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 241821.

The product of its digits is 193536, while the sum is 43.

The spelling of 643826721211 in words is "six hundred forty-three billion, eight hundred twenty-six million, seven hundred twenty-one thousand, two hundred eleven".