197897561 has 4 divisors (see below), whose sum is σ = 209538612. Its totient is φ = 186256512.

The previous prime is 197897551. The next prime is 197897569. The reversal of 197897561 is 165798791.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 181413961 + 16483600 = 13469^2 + 4060^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-197897561 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (197897569) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5820500 + ... + 5820533.

It is an arithmetic number, because the mean of its divisors is an integer number (52384653).

Almost surely, 2^197897561 is an apocalyptic number.

It is an amenable number.

197897561 is a deficient number, since it is larger than the sum of its proper divisors (11641051).

197897561 is a wasteful number, since it uses less digits than its factorization.

197897561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11641050.

The product of its digits is 952560, while the sum is 53.

The square root of 197897561 is about 14067.6067971777. The cubic root of 197897561 is about 582.7471352747.

The spelling of 197897561 in words is "one hundred ninety-seven million, eight hundred ninety-seven thousand, five hundred sixty-one".