31201233221 has 2 divisors, whose sum is σ = 31201233222. Its totient is φ = 31201233220.

The previous prime is 31201233113. The next prime is 31201233223. The reversal of 31201233221 is 12233210213.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 30551544100 + 649689121 = 174790^2 + 25489^2 .

It is a cyclic number.

It is not a de Polignac number, because 31201233221 - 2¹⁰ = 31201232197 is a prime.

It is a super-2 number, since 2×31201233221² (a number of 22 digits) contains 22 as substring.

It is a Sophie Germain prime.

Together with 31201233223, it forms a pair of twin primes.

It is a Chen prime.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 31201233193 and 31201233202.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (31201233223) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15600616610 + 15600616611.

It is an arithmetic number, because the mean of its divisors is an integer number (15600616611).

Almost surely, 2^31201233221 is an apocalyptic number.

It is an amenable number.

31201233221 is a deficient number, since it is larger than the sum of its proper divisors (1).

31201233221 is an equidigital number, since it uses as much as digits as its factorization.

31201233221 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 432, while the sum is 20.

Adding to 31201233221 its reverse (12233210213), we get a palindrome (43434443434).

The spelling of 31201233221 in words is "thirty-one billion, two hundred one million, two hundred thirty-three thousand, two hundred twenty-one".