161650009 has 2 divisors, whose sum is σ = 161650010. Its totient is φ = 161650008.

The previous prime is 161650007. The next prime is 161650019. The reversal of 161650009 is 900056161.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 113486409 + 48163600 = 10653^2 + 6940^2 .

It is a cyclic number.

It is not a de Polignac number, because 161650009 - 2¹ = 161650007 is a prime.

It is a super-2 number, since 2×161650009² = 52261450819400162, which contains 22 as substring.

Together with 161650007, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (161650001) 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, 80825004 + 80825005.

It is an arithmetic number, because the mean of its divisors is an integer number (80825005).

Almost surely, 2^161650009 is an apocalyptic number.

It is an amenable number.

161650009 is a deficient number, since it is larger than the sum of its proper divisors (1).

161650009 is an equidigital number, since it uses as much as digits as its factorization.

161650009 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1620, while the sum is 28.

The square root of 161650009 is about 12714.1656824190. The cubic root of 161650009 is about 544.7433171093.

The spelling of 161650009 in words is "one hundred sixty-one million, six hundred fifty thousand, nine".