215306 has 24 divisors (see below), whose sum is σ = 406980. Its totient is φ = 85176.

The previous prime is 215297. The next prime is 215309. The reversal of 215306 is 603512.

215306 is digitally balanced in base 3, 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 67081 + 148225 = 259^2 + 385^2 .

It is a nialpdrome in base 13.

It is a zygodrome in base 13.

It is not an unprimeable number, because it can be changed into a prime (215309) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 16556 + ... + 16568.

2²¹⁵³⁰⁶ is an apocalyptic number.

215306 is a gapful number since it is divisible by the number (26) formed by its first and last digit.

215306 is a deficient number, since it is larger than the sum of its proper divisors (191674).

215306 is an equidigital number, since it uses as much as digits as its factorization.

215306 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 55 (or 22 counting only the distinct ones).

The product of its (nonzero) digits is 180, while the sum is 17.

The square root of 215306 is about 464.0107757369. The cubic root of 215306 is about 59.9356717968.

Adding to 215306 its reverse (603512), we get a palindrome (818818).

The spelling of 215306 in words is "two hundred fifteen thousand, three hundred six".