215209243 has 4 divisors (see below), whose sum is σ = 215336880. Its totient is φ = 215081608.

The previous prime is 215209237. The next prime is 215209271. The reversal of 215209243 is 342902512.

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

It is a cyclic number.

It is not a de Polignac number, because 215209243 - 2²¹ = 213112091 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (215209283) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 61255 + ... + 64672.

It is an arithmetic number, because the mean of its divisors is an integer number (53834220).

Almost surely, 2^215209243 is an apocalyptic number.

215209243 is a deficient number, since it is larger than the sum of its proper divisors (127637).

215209243 is a wasteful number, since it uses less digits than its factorization.

215209243 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 127636.

The product of its (nonzero) digits is 4320, while the sum is 28.

The square root of 215209243 is about 14670.0116905202. The cubic root of 215209243 is about 599.2669222858.

The spelling of 215209243 in words is "two hundred fifteen million, two hundred nine thousand, two hundred forty-three".