3721321233221 has 4 divisors (see below), whose sum is σ = 3940222482252. Its totient is φ = 3502419984192.

The previous prime is 3721321233209. The next prime is 3721321233229. The reversal of 3721321233221 is 1223321231273.

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

It can be written as a sum of positive squares in 2 ways, for example, as 2131275892321 + 1590045340900 = 1459889^2 + 1260970^2 .

It is a cyclic number.

It is not a de Polignac number, because 3721321233221 - 2¹⁸ = 3721320971077 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 (3721321233229) 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, 109450624490 + ... + 109450624523.

It is an arithmetic number, because the mean of its divisors is an integer number (985055620563).

Almost surely, 2^{3721321233221} is an apocalyptic number.

It is an amenable number.

3721321233221 is a deficient number, since it is larger than the sum of its proper divisors (218901249031).

3721321233221 is a wasteful number, since it uses less digits than its factorization.

3721321233221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 218901249030.

The product of its digits is 18144, while the sum is 32.

Adding to 3721321233221 its reverse (1223321231273), we get a palindrome (4944642464494).

The spelling of 3721321233221 in words is "three trillion, seven hundred twenty-one billion, three hundred twenty-one million, two hundred thirty-three thousand, two hundred twenty-one".