161782238881 has 2 divisors, whose sum is σ = 161782238882. Its totient is φ = 161782238880.

The previous prime is 161782238873. The next prime is 161782238923. The reversal of 161782238881 is 188832287161.

161782238881 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 132289328656 + 29492910225 = 363716^2 + 171735^2 .

It is a cyclic number.

It is not a de Polignac number, because 161782238881 - 2³ = 161782238873 is a prime.

It is a super-2 number, since 2×161782238881² (a number of 23 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (161782239881) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 80891119440 + 80891119441.

It is an arithmetic number, because the mean of its divisors is an integer number (80891119441).

Almost surely, 2^161782238881 is an apocalyptic number.

It is an amenable number.

161782238881 is a deficient number, since it is larger than the sum of its proper divisors (1).

161782238881 is an equidigital number, since it uses as much as digits as its factorization.

161782238881 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2064384, while the sum is 55.

The spelling of 161782238881 in words is "one hundred sixty-one billion, seven hundred eighty-two million, two hundred thirty-eight thousand, eight hundred eighty-one".