161916191 has 2 divisors, whose sum is σ = 161916192. Its totient is φ = 161916190.

The previous prime is 161916173. The next prime is 161916217. The reversal of 161916191 is 191619161.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 161916191 - 2¹⁴ = 161899807 is a prime.

161916191 is a strobogrammatic number because it is the same when read upside-down.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (161916691) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 80958095 + 80958096.

It is an arithmetic number, because the mean of its divisors is an integer number (80958096).

Almost surely, 2^161916191 is an apocalyptic number.

161916191 is a deficient number, since it is larger than the sum of its proper divisors (1).

161916191 is an equidigital number, since it uses as much as digits as its factorization.

161916191 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2916, while the sum is 35.

The square root of 161916191 is about 12724.6293069779. The cubic root of 161916191 is about 545.0421548068.

The spelling of 161916191 in words is "one hundred sixty-one million, nine hundred sixteen thousand, one hundred ninety-one".