199121839 has 6 divisors (see below), whose sum is σ = 231631584. Its totient is φ = 170675820.

The previous prime is 199121821. The next prime is 199121851. The reversal of 199121839 is 938121991.

It is not a de Polignac number, because 199121839 - 2⁵ = 199121807 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 199121795 and 199121804.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (199121869) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 2031807 + ... + 2031904.

It is an arithmetic number, because the mean of its divisors is an integer number (38605264).

Almost surely, 2^199121839 is an apocalyptic number.

199121839 is a deficient number, since it is larger than the sum of its proper divisors (32509745).

199121839 is an equidigital number, since it uses as much as digits as its factorization.

199121839 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4063725 (or 4063718 counting only the distinct ones).

The product of its digits is 34992, while the sum is 43.

The square root of 199121839 is about 14111.0537877226. The cubic root of 199121839 is about 583.9463724057.

The spelling of 199121839 in words is "one hundred ninety-nine million, one hundred twenty-one thousand, eight hundred thirty-nine".