31231220935181 has 2 divisors, whose sum is σ = 31231220935182. Its totient is φ = 31231220935180.

The previous prime is 31231220935177. The next prime is 31231220935217. The reversal of 31231220935181 is 18153902213213.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 18969212993956 + 12262007941225 = 4355366^2 + 3501715^2 .

It is a cyclic number.

It is not a de Polignac number, because 31231220935181 - 2² = 31231220935177 is a prime.

It is a super-2 number, since 2×31231220935181² (a number of 28 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (31231220935151) 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, 15615610467590 + 15615610467591.

It is an arithmetic number, because the mean of its divisors is an integer number (15615610467591).

Almost surely, 2^{31231220935181} is an apocalyptic number.

It is an amenable number.

31231220935181 is a deficient number, since it is larger than the sum of its proper divisors (1).

31231220935181 is an equidigital number, since it uses as much as digits as its factorization.

31231220935181 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 77760, while the sum is 41.

The spelling of 31231220935181 in words is "thirty-one trillion, two hundred thirty-one billion, two hundred twenty million, nine hundred thirty-five thousand, one hundred eighty-one".