199816394 has 4 divisors (see below), whose sum is σ = 299724594. Its totient is φ = 99908196.

The previous prime is 199816381. The next prime is 199816423. The reversal of 199816394 is 493618991.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 493618991 = 227 ⋅2174533.

It can be written as a sum of positive squares in only one way, i.e., 144120025 + 55696369 = 12005^2 + 7463^2 .

It is a super-2 number, since 2×199816394² = 79853182622326472, which contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 49954097 + ... + 49954100.

Almost surely, 2^199816394 is an apocalyptic number.

199816394 is a deficient number, since it is larger than the sum of its proper divisors (99908200).

199816394 is an equidigital number, since it uses as much as digits as its factorization.

199816394 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 99908199.

The product of its digits is 419904, while the sum is 50.

The square root of 199816394 is about 14135.6426808264. The cubic root of 199816394 is about 584.6245371188.

The spelling of 199816394 in words is "one hundred ninety-nine million, eight hundred sixteen thousand, three hundred ninety-four".