199039021 has 4 divisors (see below), whose sum is σ = 204418492. Its totient is φ = 193659552.

The previous prime is 199038979. The next prime is 199039039. The reversal of 199039021 is 120930991.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 120930991 = 19 ⋅6364789.

It can be written as a sum of positive squares in 2 ways, for example, as 161645796 + 37393225 = 12714^2 + 6115^2 .

It is a cyclic number.

It is not a de Polignac number, because 199039021 - 2⁷ = 199038893 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 (199039081) 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, 2689680 + ... + 2689753.

It is an arithmetic number, because the mean of its divisors is an integer number (51104623).

Almost surely, 2^199039021 is an apocalyptic number.

It is an amenable number.

199039021 is a deficient number, since it is larger than the sum of its proper divisors (5379471).

199039021 is an equidigital number, since it uses as much as digits as its factorization.

199039021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5379470.

The product of its (nonzero) digits is 4374, while the sum is 34.

The square root of 199039021 is about 14108.1189745480. The cubic root of 199039021 is about 583.8654035924.

The spelling of 199039021 in words is "one hundred ninety-nine million, thirty-nine thousand, twenty-one".