31221222131 has 4 divisors (see below), whose sum is σ = 34059515064. Its totient is φ = 28382929200.

The previous prime is 31221222127. The next prime is 31221222203. The reversal of 31221222131 is 13122212213.

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

It is a cyclic number.

It is not a de Polignac number, because 31221222131 - 2² = 31221222127 is a prime.

It is a super-2 number, since 2×31221222131² (a number of 22 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (31221222631) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1419146450 + ... + 1419146471.

It is an arithmetic number, because the mean of its divisors is an integer number (8514878766).

Almost surely, 2^31221222131 is an apocalyptic number.

31221222131 is a deficient number, since it is larger than the sum of its proper divisors (2838292933).

31221222131 is a wasteful number, since it uses less digits than its factorization.

31221222131 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2838292932.

The product of its digits is 288, while the sum is 20.

Adding to 31221222131 its reverse (13122212213), we get a palindrome (44343434344).

It can be divided in two parts, 31221 and 222131, that added together give a palindrome (253352).

The spelling of 31221222131 in words is "thirty-one billion, two hundred twenty-one million, two hundred twenty-two thousand, one hundred thirty-one".