31233221081 has 2 divisors, whose sum is σ = 31233221082. Its totient is φ = 31233221080.

The previous prime is 31233221077. The next prime is 31233221087. The reversal of 31233221081 is 18012233213.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 30541057600 + 692163481 = 174760^2 + 26309^2 .

It is a cyclic number.

It is not a de Polignac number, because 31233221081 - 2² = 31233221077 is a prime.

It is a super-2 number, since 2×31233221081² (a number of 22 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 31233221081.

It is not a weakly prime, because it can be changed into another prime (31233221087) 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, 15616610540 + 15616610541.

It is an arithmetic number, because the mean of its divisors is an integer number (15616610541).

Almost surely, 2^31233221081 is an apocalyptic number.

It is an amenable number.

31233221081 is a deficient number, since it is larger than the sum of its proper divisors (1).

31233221081 is an equidigital number, since it uses as much as digits as its factorization.

31233221081 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1728, while the sum is 26.

Adding to 31233221081 its reverse (18012233213), we get a palindrome (49245454294).

The spelling of 31233221081 in words is "thirty-one billion, two hundred thirty-three million, two hundred twenty-one thousand, eighty-one".