161555723137 has 2 divisors, whose sum is σ = 161555723138. Its totient is φ = 161555723136.

The previous prime is 161555723107. The next prime is 161555723177. The reversal of 161555723137 is 731327555161.

161555723137 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., 156872237041 + 4683486096 = 396071^2 + 68436^2 .

It is a cyclic number.

It is not a de Polignac number, because 161555723137 - 2⁷ = 161555723009 is a prime.

It is a super-2 number, since 2×161555723137² (a number of 23 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (161555723107) 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, 80777861568 + 80777861569.

It is an arithmetic number, because the mean of its divisors is an integer number (80777861569).

Almost surely, 2^161555723137 is an apocalyptic number.

It is an amenable number.

161555723137 is a deficient number, since it is larger than the sum of its proper divisors (1).

161555723137 is an equidigital number, since it uses as much as digits as its factorization.

161555723137 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 661500, while the sum is 46.

The spelling of 161555723137 in words is "one hundred sixty-one billion, five hundred fifty-five million, seven hundred twenty-three thousand, one hundred thirty-seven".