197609809 has 2 divisors, whose sum is σ = 197609810. Its totient is φ = 197609808.

The previous prime is 197609807. The next prime is 197609831. The reversal of 197609809 is 908906791.

197609809 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 197318209 + 291600 = 14047^2 + 540^2 .

It is a cyclic number.

It is not a de Polignac number, because 197609809 - 2¹ = 197609807 is a prime.

It is a super-2 number, since 2×197609809² = 78099273226032962, which contains 22 as substring.

Together with 197609807, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (197609807) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 98804904 + 98804905.

It is an arithmetic number, because the mean of its divisors is an integer number (98804905).

Almost surely, 2^197609809 is an apocalyptic number.

It is an amenable number.

197609809 is a deficient number, since it is larger than the sum of its proper divisors (1).

197609809 is an equidigital number, since it uses as much as digits as its factorization.

197609809 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 244944, while the sum is 49.

The square root of 197609809 is about 14057.3756085551. The cubic root of 197609809 is about 582.4645513742.

The spelling of 197609809 in words is "one hundred ninety-seven million, six hundred nine thousand, eight hundred nine".