643255426211 has 4 divisors (see below), whose sum is σ = 681093980712. Its totient is φ = 605416871712.

The previous prime is 643255426199. The next prime is 643255426273. The reversal of 643255426211 is 112624552346.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-643255426211 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (643255426111) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 18919277225 + ... + 18919277258.

It is an arithmetic number, because the mean of its divisors is an integer number (170273495178).

Almost surely, 2^643255426211 is an apocalyptic number.

643255426211 is a deficient number, since it is larger than the sum of its proper divisors (37838554501).

643255426211 is a wasteful number, since it uses less digits than its factorization.

643255426211 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 37838554500.

The product of its digits is 345600, while the sum is 41.

Adding to 643255426211 its reverse (112624552346), we get a palindrome (755879978557).

The spelling of 643255426211 in words is "six hundred forty-three billion, two hundred fifty-five million, four hundred twenty-six thousand, two hundred eleven".