199809557 has 4 divisors (see below), whose sum is σ = 199902060. Its totient is φ = 199717056.

The previous prime is 199809521. The next prime is 199809563. The reversal of 199809557 is 755908991.

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 197852356 + 1957201 = 14066^2 + 1399^2 .

It is a cyclic number.

It is not a de Polignac number, because 199809557 - 2¹⁰ = 199808533 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 199809499 and 199809508.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (199809457) 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, 42932 + ... + 47357.

It is an arithmetic number, because the mean of its divisors is an integer number (49975515).

Almost surely, 2^199809557 is an apocalyptic number.

It is an amenable number.

199809557 is a deficient number, since it is larger than the sum of its proper divisors (92503).

199809557 is an equidigital number, since it uses as much as digits as its factorization.

199809557 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 92502.

The product of its (nonzero) digits is 1020600, while the sum is 53.

The square root of 199809557 is about 14135.4008432729. The cubic root of 199809557 is about 584.6178691248.

The spelling of 199809557 in words is "one hundred ninety-nine million, eight hundred nine thousand, five hundred fifty-seven".