213837209 has 4 divisors (see below), whose sum is σ = 214049316. Its totient is φ = 213625104.

The previous prime is 213837199. The next prime is 213837227. The reversal of 213837209 is 902738312.

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

It can be written as a sum of positive squares in 2 ways, for example, as 14462809 + 199374400 = 3803^2 + 14120^2 .

It is a cyclic number.

It is not a de Polignac number, because 213837209 - 2⁴ = 213837193 is a prime.

It is a super-3 number, since 3×213837209³ (a number of 26 digits) contains 333 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (213837259) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 104534 + ... + 106559.

It is an arithmetic number, because the mean of its divisors is an integer number (53512329).

Almost surely, 2^213837209 is an apocalyptic number.

It is an amenable number.

213837209 is a deficient number, since it is larger than the sum of its proper divisors (212107).

213837209 is a wasteful number, since it uses less digits than its factorization.

213837209 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 212106.

The product of its (nonzero) digits is 18144, while the sum is 35.

The square root of 213837209 is about 14623.1736979358. The cubic root of 213837209 is about 597.9906944037.

The spelling of 213837209 in words is "two hundred thirteen million, eight hundred thirty-seven thousand, two hundred nine".