161505569 has 2 divisors, whose sum is σ = 161505570. Its totient is φ = 161505568.

The previous prime is 161505521. The next prime is 161505599. The reversal of 161505569 is 965505161.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 157753600 + 3751969 = 12560^2 + 1937^2 .

It is a cyclic number.

It is not a de Polignac number, because 161505569 - 2⁸ = 161505313 is a prime.

It is a super-2 number, since 2×161505569² = 52168097636027522, which contains 22 as substring.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (161505599) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 80752784 + 80752785.

It is an arithmetic number, because the mean of its divisors is an integer number (80752785).

Almost surely, 2^161505569 is an apocalyptic number.

It is an amenable number.

161505569 is a deficient number, since it is larger than the sum of its proper divisors (1).

161505569 is an equidigital number, since it uses as much as digits as its factorization.

161505569 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 40500, while the sum is 38.

The square root of 161505569 is about 12708.4841346244. The cubic root of 161505569 is about 544.5810196203.

The spelling of 161505569 in words is "one hundred sixty-one million, five hundred five thousand, five hundred sixty-nine".