197786161 has 2 divisors, whose sum is σ = 197786162. Its totient is φ = 197786160.

The previous prime is 197786159. The next prime is 197786167. The reversal of 197786161 is 161687791.

197786161 = 9944² + 9945².

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 98903025 + 98883136 = 9945^2 + 9944^2 .

It is an emirp because it is prime and its reverse (161687791) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 197786161 - 2¹ = 197786159 is a prime.

Together with 197786159, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (197786167) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 98893080 + 98893081.

It is an arithmetic number, because the mean of its divisors is an integer number (98893081).

Almost surely, 2^197786161 is an apocalyptic number.

197786161 is the 9945-th centered square number.

It is an amenable number.

197786161 is a deficient number, since it is larger than the sum of its proper divisors (1).

197786161 is an equidigital number, since it uses as much as digits as its factorization.

197786161 is an evil number, because the sum of its binary digits is even.

The product of its digits is 127008, while the sum is 46.

The square root of 197786161 is about 14063.6467887956. The cubic root of 197786161 is about 582.6377685641.

The spelling of 197786161 in words is "one hundred ninety-seven million, seven hundred eighty-six thousand, one hundred sixty-one".