197678861 has 2 divisors, whose sum is σ = 197678862. Its totient is φ = 197678860.

The previous prime is 197678849. The next prime is 197678863. The reversal of 197678861 is 168876791.

197678861 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 137616361 + 60062500 = 11731^2 + 7750^2 .

It is a cyclic number.

It is not a de Polignac number, because 197678861 - 2⁶ = 197678797 is a prime.

Together with 197678863, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (197678863) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 98839430 + 98839431.

It is an arithmetic number, because the mean of its divisors is an integer number (98839431).

Almost surely, 2^197678861 is an apocalyptic number.

It is an amenable number.

197678861 is a deficient number, since it is larger than the sum of its proper divisors (1).

197678861 is an equidigital number, since it uses as much as digits as its factorization.

197678861 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1016064, while the sum is 53.

The square root of 197678861 is about 14059.8314712517. The cubic root of 197678861 is about 582.5323881860.

The spelling of 197678861 in words is "one hundred ninety-seven million, six hundred seventy-eight thousand, eight hundred sixty-one".