161913109 has 2 divisors, whose sum is σ = 161913110. Its totient is φ = 161913108.

The previous prime is 161913091. The next prime is 161913113. The reversal of 161913109 is 901319161.

Together with previous prime (161913091) it forms an Ormiston pair, because they use the same digits, order apart.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 146531025 + 15382084 = 12105^2 + 3922^2 .

It is a cyclic number.

It is not a de Polignac number, because 161913109 - 2²⁵ = 128358677 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (161913509) 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, 80956554 + 80956555.

It is an arithmetic number, because the mean of its divisors is an integer number (80956555).

Almost surely, 2^161913109 is an apocalyptic number.

It is an amenable number.

161913109 is a deficient number, since it is larger than the sum of its proper divisors (1).

161913109 is an equidigital number, since it uses as much as digits as its factorization.

161913109 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1458, while the sum is 31.

The square root of 161913109 is about 12724.5082026772. The cubic root of 161913109 is about 545.0386965762.

The spelling of 161913109 in words is "one hundred sixty-one million, nine hundred thirteen thousand, one hundred nine".