844167185681 has 2 divisors, whose sum is σ = 844167185682. Its totient is φ = 844167185680.

The previous prime is 844167185633. The next prime is 844167185801. The reversal of 844167185681 is 186581761448.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 788471185681 + 55696000000 = 887959^2 + 236000^2 .

It is a cyclic number.

It is not a de Polignac number, because 844167185681 - 2²² = 844162991377 is a prime.

It is a super-2 number, since 2×844167185681² (a number of 25 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 844167185681.

It is not a weakly prime, because it can be changed into another prime (844167181681) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 422083592840 + 422083592841.

It is an arithmetic number, because the mean of its divisors is an integer number (422083592841).

Almost surely, 2^844167185681 is an apocalyptic number.

It is an amenable number.

844167185681 is a deficient number, since it is larger than the sum of its proper divisors (1).

844167185681 is an equidigital number, since it uses as much as digits as its factorization.

844167185681 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 10321920, while the sum is 59.

The spelling of 844167185681 in words is "eight hundred forty-four billion, one hundred sixty-seven million, one hundred eighty-five thousand, six hundred eighty-one".