161045561 has 2 divisors, whose sum is σ = 161045562. Its totient is φ = 161045560.

The previous prime is 161045557. The next prime is 161045579. The reversal of 161045561 is 165540161.

161045561 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., 155475961 + 5569600 = 12469^2 + 2360^2 .

It is an emirp because it is prime and its reverse (165540161) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 161045561 - 2² = 161045557 is a prime.

It is not a weakly prime, because it can be changed into another prime (161045461) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 80522780 + 80522781.

It is an arithmetic number, because the mean of its divisors is an integer number (80522781).

Almost surely, 2^161045561 is an apocalyptic number.

It is an amenable number.

161045561 is a deficient number, since it is larger than the sum of its proper divisors (1).

161045561 is an equidigital number, since it uses as much as digits as its factorization.

161045561 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 3600, while the sum is 29.

The square root of 161045561 is about 12690.3727683626. The cubic root of 161045561 is about 544.0634939315.

The spelling of 161045561 in words is "one hundred sixty-one million, forty-five thousand, five hundred sixty-one".