643221333421 has 8 divisors (see below), whose sum is σ = 645069934080. Its totient is φ = 641373397392.

The previous prime is 643221333409. The next prime is 643221333437. The reversal of 643221333421 is 124333122346.

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 643221333421 - 2³³ = 634631398829 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 (643221313421) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1805736 + ... + 2132398.

It is an arithmetic number, because the mean of its divisors is an integer number (80633741760).

Almost surely, 2^643221333421 is an apocalyptic number.

It is an amenable number.

643221333421 is a deficient number, since it is larger than the sum of its proper divisors (1848600659).

643221333421 is a wasteful number, since it uses less digits than its factorization.

643221333421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 332315.

The product of its digits is 62208, while the sum is 34.

Adding to 643221333421 its reverse (124333122346), we get a palindrome (767554455767).

The spelling of 643221333421 in words is "six hundred forty-three billion, two hundred twenty-one million, three hundred thirty-three thousand, four hundred twenty-one".