161506109 has 2 divisors, whose sum is σ = 161506110. Its totient is φ = 161506108.

The previous prime is 161506097. The next prime is 161506123. The reversal of 161506109 is 901605161.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 111408025 + 50098084 = 10555^2 + 7078^2 .

It is an emirp because it is prime and its reverse (901605161) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 161506109 - 2⁸ = 161505853 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (161506159) 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, 80753054 + 80753055.

It is an arithmetic number, because the mean of its divisors is an integer number (80753055).

Almost surely, 2^161506109 is an apocalyptic number.

It is an amenable number.

161506109 is a deficient number, since it is larger than the sum of its proper divisors (1).

161506109 is an equidigital number, since it uses as much as digits as its factorization.

161506109 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 29.

The square root of 161506109 is about 12708.5053802562. The cubic root of 161506109 is about 544.5816265621.

The spelling of 161506109 in words is "one hundred sixty-one million, five hundred six thousand, one hundred nine".