161205570961 has 2 divisors, whose sum is σ = 161205570962. Its totient is φ = 161205570960.

The previous prime is 161205570959. The next prime is 161205571183. The reversal of 161205570961 is 169075502161.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 135659622400 + 25545948561 = 368320^2 + 159831^2 .

It is a cyclic number.

It is not a de Polignac number, because 161205570961 - 2¹ = 161205570959 is a prime.

It is a super-2 number, since 2×161205570961² (a number of 23 digits) contains 22 as substring.

Together with 161205570959, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (161205570061) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 80602785480 + 80602785481.

It is an arithmetic number, because the mean of its divisors is an integer number (80602785481).

Almost surely, 2^161205570961 is an apocalyptic number.

It is an amenable number.

161205570961 is a deficient number, since it is larger than the sum of its proper divisors (1).

161205570961 is an equidigital number, since it uses as much as digits as its factorization.

161205570961 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 113400, while the sum is 43.

The spelling of 161205570961 in words is "one hundred sixty-one billion, two hundred five million, five hundred seventy thousand, nine hundred sixty-one".