321131221 has 4 divisors (see below), whose sum is σ = 335093472. Its totient is φ = 307168972.

The previous prime is 321131219. The next prime is 321131231. The reversal of 321131221 is 122131123.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 321131221 - 2¹ = 321131219 is a prime.

It is a super-2 number, since 2×321131221² = 206250522201901682, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 321131195 and 321131204.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (321131231) 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, 6981091 + ... + 6981136.

It is an arithmetic number, because the mean of its divisors is an integer number (83773368).

Almost surely, 2^321131221 is an apocalyptic number.

It is an amenable number.

321131221 is a deficient number, since it is larger than the sum of its proper divisors (13962251).

321131221 is a wasteful number, since it uses less digits than its factorization.

321131221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13962250.

The product of its digits is 72, while the sum is 16.

The square root of 321131221 is about 17920.1345140041. The cubic root of 321131221 is about 684.7954144217.

Adding to 321131221 its reverse (122131123), we get a palindrome (443262344).

The spelling of 321131221 in words is "three hundred twenty-one million, one hundred thirty-one thousand, two hundred twenty-one".