31221121321 has 8 divisors (see below), whose sum is σ = 34173939464. Its totient is φ = 28347045120.

The previous prime is 31221121307. The next prime is 31221121363. The reversal of 31221121321 is 12312112213.

It can be written as a sum of positive squares in 4 ways, for example, as 2385345600 + 28835775721 = 48840^2 + 169811^2 .

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 31221121321 - 2⁷ = 31221121193 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (31221121301) 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, 19684656 + ... + 19686241.

It is an arithmetic number, because the mean of its divisors is an integer number (4271742433).

Almost surely, 2^31221121321 is an apocalyptic number.

It is an amenable number.

31221121321 is a deficient number, since it is larger than the sum of its proper divisors (2952818143).

31221121321 is a wasteful number, since it uses less digits than its factorization.

31221121321 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 39370971.

The product of its digits is 144, while the sum is 19.

Adding to 31221121321 its reverse (12312112213), we get a palindrome (43533233534).

The spelling of 31221121321 in words is "thirty-one billion, two hundred twenty-one million, one hundred twenty-one thousand, three hundred twenty-one".