161641544789 has 2 divisors, whose sum is σ = 161641544790. Its totient is φ = 161641544788.

The previous prime is 161641544783. The next prime is 161641544803. The reversal of 161641544789 is 987445146161.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 154737596689 + 6903948100 = 393367^2 + 83090^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-161641544789 is a prime.

It is a super-2 number, since 2×161641544789² (a number of 23 digits) contains 22 as substring.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (161641544783) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 80820772394 + 80820772395.

It is an arithmetic number, because the mean of its divisors is an integer number (80820772395).

Almost surely, 2^161641544789 is an apocalyptic number.

It is an amenable number.

161641544789 is a deficient number, since it is larger than the sum of its proper divisors (1).

161641544789 is an equidigital number, since it uses as much as digits as its factorization.

161641544789 is an evil number, because the sum of its binary digits is even.

The product of its digits is 5806080, while the sum is 56.

The spelling of 161641544789 in words is "one hundred sixty-one billion, six hundred forty-one million, five hundred forty-four thousand, seven hundred eighty-nine".