213309 has 12 divisors (see below), whose sum is σ = 312156. Its totient is φ = 140352.

The previous prime is 213307. The next prime is 213319. The reversal of 213309 is 903312.

213309 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 2 ways, for example, as 164025 + 49284 = 405^2 + 222^2 .

It is not a de Polignac number, because 213309 - 2¹ = 213307 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 213291 and 213300.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (213307) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1147 + ... + 1319.

It is an arithmetic number, because the mean of its divisors is an integer number (26013).

2²¹³³⁰⁹ is an apocalyptic number.

It is an amenable number.

213309 is a deficient number, since it is larger than the sum of its proper divisors (98847).

213309 is a wasteful number, since it uses less digits than its factorization.

213309 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 316 (or 313 counting only the distinct ones).

The product of its (nonzero) digits is 162, while the sum is 18.

The square root of 213309 is about 461.8538729945. The cubic root of 213309 is about 59.7497913778.

The spelling of 213309 in words is "two hundred thirteen thousand, three hundred nine".