216823213 has 4 divisors (see below), whose sum is σ = 219793468. Its totient is φ = 213852960.

The previous prime is 216823199. The next prime is 216823241. The reversal of 216823213 is 312328612.

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 69006249 + 147816964 = 8307^2 + 12158^2 .

It is a cyclic number.

It is not a de Polignac number, because 216823213 - 2¹⁷ = 216692141 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 (216823273) 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, 1485018 + ... + 1485163.

It is an arithmetic number, because the mean of its divisors is an integer number (54948367).

Almost surely, 2^216823213 is an apocalyptic number.

It is an amenable number.

216823213 is a deficient number, since it is larger than the sum of its proper divisors (2970255).

216823213 is an equidigital number, since it uses as much as digits as its factorization.

216823213 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2970254.

The product of its digits is 3456, while the sum is 28.

The square root of 216823213 is about 14724.9180982442. The cubic root of 216823213 is about 600.7612679692.

The spelling of 216823213 in words is "two hundred sixteen million, eight hundred twenty-three thousand, two hundred thirteen".