31121100181 has 2 divisors, whose sum is σ = 31121100182. Its totient is φ = 31121100180.

The previous prime is 31121100163. The next prime is 31121100203. The reversal of 31121100181 is 18100112113.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 28431018225 + 2690081956 = 168615^2 + 51866^2 .

It is a cyclic number.

It is not a de Polignac number, because 31121100181 - 2⁷ = 31121100053 is a prime.

It is a super-2 number, since 2×31121100181² (a number of 22 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (31121101181) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15560550090 + 15560550091.

It is an arithmetic number, because the mean of its divisors is an integer number (15560550091).

Almost surely, 2^31121100181 is an apocalyptic number.

It is an amenable number.

31121100181 is a deficient number, since it is larger than the sum of its proper divisors (1).

31121100181 is an equidigital number, since it uses as much as digits as its factorization.

31121100181 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 48, while the sum is 19.

Adding to 31121100181 its reverse (18100112113), we get a palindrome (49221212294).

The spelling of 31121100181 in words is "thirty-one billion, one hundred twenty-one million, one hundred thousand, one hundred eighty-one".