197947909 has 4 divisors (see below), whose sum is σ = 208366240. Its totient is φ = 187529580.

The previous prime is 197947907. The next prime is 197947961. The reversal of 197947909 is 909749791.

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: 909749791 = 61 ⋅14913931.

It is a cyclic number.

It is not a de Polignac number, because 197947909 - 2¹ = 197947907 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 197947909.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (197947901) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5209137 + ... + 5209174.

It is an arithmetic number, because the mean of its divisors is an integer number (52091560).

Almost surely, 2^197947909 is an apocalyptic number.

197947909 is a gapful number since it is divisible by the number (19) formed by its first and last digit.

It is an amenable number.

197947909 is a deficient number, since it is larger than the sum of its proper divisors (10418331).

197947909 is a wasteful number, since it uses less digits than its factorization.

197947909 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10418330.

The product of its (nonzero) digits is 1285956, while the sum is 55.

The square root of 197947909 is about 14069.3961846271. The cubic root of 197947909 is about 582.7965508490.

The spelling of 197947909 in words is "one hundred ninety-seven million, nine hundred forty-seven thousand, nine hundred nine".