31233221 has 2 divisors, whose sum is σ = 31233222. Its totient is φ = 31233220.

The previous prime is 31233121. The next prime is 31233227. The reversal of 31233221 is 12233213.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 20376196 + 10857025 = 4514^2 + 3295^2 .

It is a cyclic number.

It is not a de Polignac number, because 31233221 - 2²² = 27038917 is a prime.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 31233221.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (31233227) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15616610 + 15616611.

It is an arithmetic number, because the mean of its divisors is an integer number (15616611).

Almost surely, 2^31233221 is an apocalyptic number.

It is an amenable number.

31233221 is a deficient number, since it is larger than the sum of its proper divisors (1).

31233221 is an equidigital number, since it uses as much as digits as its factorization.

31233221 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 216, while the sum is 17.

The square root of 31233221 is about 5588.6689828617. The cubic root of 31233221 is about 314.9238784737.

Adding to 31233221 its reverse (12233213), we get a palindrome (43466434).

It can be divided in two parts, 312 and 33221, that added together give a palindrome (33533).

The spelling of 31233221 in words is "thirty-one million, two hundred thirty-three thousand, two hundred twenty-one".