161215309 has 2 divisors, whose sum is σ = 161215310. Its totient is φ = 161215308.

The previous prime is 161215289. The next prime is 161215319. The reversal of 161215309 is 903512161.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 83722500 + 77492809 = 9150^2 + 8803^2 .

It is a cyclic number.

It is not a de Polignac number, because 161215309 - 2⁷ = 161215181 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (161215319) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 80607654 + 80607655.

It is an arithmetic number, because the mean of its divisors is an integer number (80607655).

Almost surely, 2^161215309 is an apocalyptic number.

It is an amenable number.

161215309 is a deficient number, since it is larger than the sum of its proper divisors (1).

161215309 is an equidigital number, since it uses as much as digits as its factorization.

161215309 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 161215309 is about 12697.0590689340. The cubic root of 161215309 is about 544.2545811831.

The spelling of 161215309 in words is "one hundred sixty-one million, two hundred fifteen thousand, three hundred nine".