197785009 has 4 divisors (see below), whose sum is σ = 197863204. Its totient is φ = 197706816.

The previous prime is 197785001. The next prime is 197785019. The reversal of 197785009 is 900587791.

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 131606784 + 66178225 = 11472^2 + 8135^2 .

It is a cyclic number.

It is not a de Polignac number, because 197785009 - 2³ = 197785001 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 197785009.

It is not an unprimeable number, because it can be changed into a prime (197785001) 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, 35172 + ... + 40405.

It is an arithmetic number, because the mean of its divisors is an integer number (49465801).

Almost surely, 2^197785009 is an apocalyptic number.

It is an amenable number.

197785009 is a deficient number, since it is larger than the sum of its proper divisors (78195).

197785009 is an equidigital number, since it uses as much as digits as its factorization.

197785009 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 78194.

The product of its (nonzero) digits is 158760, while the sum is 46.

The square root of 197785009 is about 14063.6058320759. The cubic root of 197785009 is about 582.6366373760.

The spelling of 197785009 in words is "one hundred ninety-seven million, seven hundred eighty-five thousand, nine".