31131220033321 has 2 divisors, whose sum is σ = 31131220033322. Its totient is φ = 31131220033320.

The previous prime is 31131220033283. The next prime is 31131220033327. The reversal of 31131220033321 is 12333002213113.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 25686296467225 + 5444923566096 = 5068165^2 + 2333436^2 .

It is a cyclic number.

It is not a de Polignac number, because 31131220033321 - 2⁴¹ = 28932196777769 is a prime.

It is not a weakly prime, because it can be changed into another prime (31131220033327) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15565610016660 + 15565610016661.

It is an arithmetic number, because the mean of its divisors is an integer number (15565610016661).

Almost surely, 2^{31131220033321} is an apocalyptic number.

It is an amenable number.

31131220033321 is a deficient number, since it is larger than the sum of its proper divisors (1).

31131220033321 is an equidigital number, since it uses as much as digits as its factorization.

31131220033321 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1944, while the sum is 25.

Adding to 31131220033321 its reverse (12333002213113), we get a palindrome (43464222246434).

The spelling of 31131220033321 in words is "thirty-one trillion, one hundred thirty-one billion, two hundred twenty million, thirty-three thousand, three hundred twenty-one".