168181681531481 has 2 divisors, whose sum is σ = 168181681531482. Its totient is φ = 168181681531480.

The previous prime is 168181681531471. The next prime is 168181681531571. The reversal of 168181681531481 is 184135186181861.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 162137336355856 + 6044345175625 = 12733316^2 + 2458525^2 .

It is a cyclic number.

It is not a de Polignac number, because 168181681531481 - 2¹⁸ = 168181681269337 is a prime.

It is a super-2 number, since 2×168181681531481² (a number of 29 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (168181681531471) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 84090840765740 + 84090840765741.

It is an arithmetic number, because the mean of its divisors is an integer number (84090840765741).

Almost surely, 2^{168181681531481} is an apocalyptic number.

It is an amenable number.

168181681531481 is a deficient number, since it is larger than the sum of its proper divisors (1).

168181681531481 is an equidigital number, since it uses as much as digits as its factorization.

168181681531481 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 8847360, while the sum is 62.

The spelling of 168181681531481 in words is "one hundred sixty-eight trillion, one hundred eighty-one billion, six hundred eighty-one million, five hundred thirty-one thousand, four hundred eighty-one".