31220121310181 has 2 divisors, whose sum is σ = 31220121310182. Its totient is φ = 31220121310180.

The previous prime is 31220121310141. The next prime is 31220121310249. The reversal of 31220121310181 is 18101312102213.

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., 29012593959556 + 2207527350625 = 5386334^2 + 1485775^2 .

It is an emirp because it is prime and its reverse (18101312102213) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 31220121310181 - 2⁴² = 26822074799077 is a prime.

It is a super-2 number, since 2×31220121310181² (a number of 28 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 31220121310181.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (31220121310141) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15610060655090 + 15610060655091.

It is an arithmetic number, because the mean of its divisors is an integer number (15610060655091).

Almost surely, 2^{31220121310181} is an apocalyptic number.

It is an amenable number.

31220121310181 is a deficient number, since it is larger than the sum of its proper divisors (1).

31220121310181 is an equidigital number, since it uses as much as digits as its factorization.

31220121310181 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 576, while the sum is 26.

Adding to 31220121310181 its reverse (18101312102213), we get a palindrome (49321433412394).

The spelling of 31220121310181 in words is "thirty-one trillion, two hundred twenty billion, one hundred twenty-one million, three hundred ten thousand, one hundred eighty-one".