197618809 has 4 divisors (see below), whose sum is σ = 198505216. Its totient is φ = 196732404.

The previous prime is 197618797. The next prime is 197618843. The reversal of 197618809 is 908816791.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 908816791 = 857 ⋅1060463.

It is a cyclic number.

It is not a de Polignac number, because 197618809 - 2¹³ = 197610617 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (197618009) 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, 442869 + ... + 443314.

It is an arithmetic number, because the mean of its divisors is an integer number (49626304).

Almost surely, 2^197618809 is an apocalyptic number.

It is an amenable number.

197618809 is a deficient number, since it is larger than the sum of its proper divisors (886407).

197618809 is an equidigital number, since it uses as much as digits as its factorization.

197618809 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 886406.

The product of its (nonzero) digits is 217728, while the sum is 49.

The square root of 197618809 is about 14057.6957215612. The cubic root of 197618809 is about 582.4733938863.

The spelling of 197618809 in words is "one hundred ninety-seven million, six hundred eighteen thousand, eight hundred nine".