199997807 has 4 divisors (see below), whose sum is σ = 200391240. Its totient is φ = 199604376.

The previous prime is 199997797. The next prime is 199997851. The reversal of 199997807 is 708799991.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 199997807 - 2¹⁸ = 199735663 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 (199997867) 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, 195953 + ... + 196970.

It is an arithmetic number, because the mean of its divisors is an integer number (50097810).

Almost surely, 2^199997807 is an apocalyptic number.

199997807 is a deficient number, since it is larger than the sum of its proper divisors (393433).

199997807 is an equidigital number, since it uses as much as digits as its factorization.

199997807 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 393432.

The product of its (nonzero) digits is 2571912, while the sum is 59.

The square root of 199997807 is about 14142.0580892599. The cubic root of 199997807 is about 584.8014101778.

The spelling of 199997807 in words is "one hundred ninety-nine million, nine hundred ninety-seven thousand, eight hundred seven".