161761609 has 2 divisors, whose sum is σ = 161761610. Its totient is φ = 161761608.

The previous prime is 161761597. The next prime is 161761661. The reversal of 161761609 is 906167161.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 159466384 + 2295225 = 12628^2 + 1515^2 .

It is a cyclic number.

It is not a de Polignac number, because 161761609 - 2⁹ = 161761097 is a prime.

It is not a weakly prime, because it can be changed into another prime (161761909) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 80880804 + 80880805.

It is an arithmetic number, because the mean of its divisors is an integer number (80880805).

Almost surely, 2^161761609 is an apocalyptic number.

It is an amenable number.

161761609 is a deficient number, since it is larger than the sum of its proper divisors (1).

161761609 is an equidigital number, since it uses as much as digits as its factorization.

161761609 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 13608, while the sum is 37.

The square root of 161761609 is about 12718.5537306724. The cubic root of 161761609 is about 544.8686483104.

The spelling of 161761609 in words is "one hundred sixty-one million, seven hundred sixty-one thousand, six hundred nine".