199998635 has 4 divisors (see below), whose sum is σ = 239998368. Its totient is φ = 159998904.

The previous prime is 199998607. The next prime is 199998637. The reversal of 199998635 is 536899991.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 536899991 = 17747 ⋅30253.

It is a cyclic number.

It is not a de Polignac number, because 199998635 - 2¹⁸ = 199736491 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (199998637) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 19999859 + ... + 19999868.

It is an arithmetic number, because the mean of its divisors is an integer number (59999592).

Almost surely, 2^199998635 is an apocalyptic number.

199998635 is a deficient number, since it is larger than the sum of its proper divisors (39999733).

199998635 is an equidigital number, since it uses as much as digits as its factorization.

199998635 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 39999732.

The product of its digits is 4723920, while the sum is 59.

The square root of 199998635 is about 14142.0873636108. The cubic root of 199998635 is about 584.8022172115.

The spelling of 199998635 in words is "one hundred ninety-nine million, nine hundred ninety-eight thousand, six hundred thirty-five".