161205281 has 2 divisors, whose sum is σ = 161205282. Its totient is φ = 161205280.

The previous prime is 161205259. The next prime is 161205293. The reversal of 161205281 is 182502161.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 116100625 + 45104656 = 10775^2 + 6716^2 .

It is a cyclic number.

It is not a de Polignac number, because 161205281 - 2⁶ = 161205217 is a prime.

It is a super-2 number, since 2×161205281² = 51974285244577922, which contains 22 as substring.

It is equal to p_9038402 and since 161205281 and 9038402 have the same sum of digits, it is a Honaker prime.

It is a self number, because there is not a number n which added to its sum of digits gives 161205281.

It is not a weakly prime, because it can be changed into another prime (161205211) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 80602640 + 80602641.

It is an arithmetic number, because the mean of its divisors is an integer number (80602641).

Almost surely, 2^161205281 is an apocalyptic number.

It is an amenable number.

161205281 is a deficient number, since it is larger than the sum of its proper divisors (1).

161205281 is an equidigital number, since it uses as much as digits as its factorization.

161205281 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 960, while the sum is 26.

The square root of 161205281 is about 12696.6641681979. The cubic root of 161205281 is about 544.2432962786.

The spelling of 161205281 in words is "one hundred sixty-one million, two hundred five thousand, two hundred eighty-one".