31223221220173 has 2 divisors, whose sum is σ = 31223221220174. Its totient is φ = 31223221220172.

The previous prime is 31223221220129. The next prime is 31223221220231. The reversal of 31223221220173 is 37102212232213.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 26403185390409 + 4820035829764 = 5138403^2 + 2195458^2 .

It is a cyclic number.

It is not a de Polignac number, because 31223221220173 - 2²⁵ = 31223187665741 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (31223221220123) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15611610610086 + 15611610610087.

It is an arithmetic number, because the mean of its divisors is an integer number (15611610610087).

Almost surely, 2^{31223221220173} is an apocalyptic number.

It is an amenable number.

31223221220173 is a deficient number, since it is larger than the sum of its proper divisors (1).

31223221220173 is an equidigital number, since it uses as much as digits as its factorization.

31223221220173 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 12096, while the sum is 31.

Adding to 31223221220173 its reverse (37102212232213), we get a palindrome (68325433452386).

The spelling of 31223221220173 in words is "thirty-one trillion, two hundred twenty-three billion, two hundred twenty-one million, two hundred twenty thousand, one hundred seventy-three".