20311331031221 has 2 divisors, whose sum is σ = 20311331031222. Its totient is φ = 20311331031220.

The previous prime is 20311331031217. The next prime is 20311331031247. The reversal of 20311331031221 is 12213013311302.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 13270640266321 + 7040690764900 = 3642889^2 + 2653430^2 .

It is a cyclic number.

It is not a de Polignac number, because 20311331031221 - 2² = 20311331031217 is a prime.

It is a super-2 number, since 2×20311331031221² (a number of 27 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20311331033221) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10155665515610 + 10155665515611.

It is an arithmetic number, because the mean of its divisors is an integer number (10155665515611).

Almost surely, 2^{20311331031221} is an apocalyptic number.

It is an amenable number.

20311331031221 is a deficient number, since it is larger than the sum of its proper divisors (1).

20311331031221 is an equidigital number, since it uses as much as digits as its factorization.

20311331031221 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 648, while the sum is 23.

Adding to 20311331031221 its reverse (12213013311302), we get a palindrome (32524344342523).

The spelling of 20311331031221 in words is "twenty trillion, three hundred eleven billion, three hundred thirty-one million, thirty-one thousand, two hundred twenty-one".