215135209 has 2 divisors, whose sum is σ = 215135210. Its totient is φ = 215135208.

The previous prime is 215135203. The next prime is 215135243. The reversal of 215135209 is 902531512.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 188457984 + 26677225 = 13728^2 + 5165^2 .

It is a cyclic number.

It is not a de Polignac number, because 215135209 - 2³ = 215135201 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (215135201) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 107567604 + 107567605.

It is an arithmetic number, because the mean of its divisors is an integer number (107567605).

Almost surely, 2^215135209 is an apocalyptic number.

It is an amenable number.

215135209 is a deficient number, since it is larger than the sum of its proper divisors (1).

215135209 is an equidigital number, since it uses as much as digits as its factorization.

215135209 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2700, while the sum is 28.

The square root of 215135209 is about 14667.4881625996. The cubic root of 215135209 is about 599.1981965887.

It can be divided in two parts, 215 and 135209, that added together give a square (135424 = 368²).

The spelling of 215135209 in words is "two hundred fifteen million, one hundred thirty-five thousand, two hundred nine".