197809397 has 4 divisors (see below), whose sum is σ = 201052236. Its totient is φ = 194566560.

The previous prime is 197809369. The next prime is 197809439. The reversal of 197809397 is 793908791.

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 102434641 + 95374756 = 10121^2 + 9766^2 .

It is a cyclic number.

It is not a de Polignac number, because 197809397 - 2⁶ = 197809333 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (197809327) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1621328 + ... + 1621449.

It is an arithmetic number, because the mean of its divisors is an integer number (50263059).

Almost surely, 2^197809397 is an apocalyptic number.

It is an amenable number.

197809397 is a deficient number, since it is larger than the sum of its proper divisors (3242839).

197809397 is an equidigital number, since it uses as much as digits as its factorization.

197809397 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3242838.

The product of its (nonzero) digits is 857304, while the sum is 53.

The square root of 197809397 is about 14064.4728660551. The cubic root of 197809397 is about 582.6605838460.

The spelling of 197809397 in words is "one hundred ninety-seven million, eight hundred nine thousand, three hundred ninety-seven".