161840197 has 4 divisors (see below), whose sum is σ = 164057260. Its totient is φ = 159623136.

The previous prime is 161840191. The next prime is 161840281. The reversal of 161840197 is 791048161.

161840197 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 791048161 = 53 ⋅14925437.

It can be written as a sum of positive squares in 2 ways, for example, as 77457601 + 84382596 = 8801^2 + 9186^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-161840197 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (161840191) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1108422 + ... + 1108567.

It is an arithmetic number, because the mean of its divisors is an integer number (41014315).

Almost surely, 2^161840197 is an apocalyptic number.

It is an amenable number.

161840197 is a deficient number, since it is larger than the sum of its proper divisors (2217063).

161840197 is an equidigital number, since it uses as much as digits as its factorization.

161840197 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2217062.

The product of its (nonzero) digits is 12096, while the sum is 37.

The square root of 161840197 is about 12721.6428577444. The cubic root of 161840197 is about 544.9568711487.

The spelling of 161840197 in words is "one hundred sixty-one million, eight hundred forty thousand, one hundred ninety-seven".