217256243 has 4 divisors (see below), whose sum is σ = 230036040. Its totient is φ = 204476448.

The previous prime is 217256239. The next prime is 217256251. The reversal of 217256243 is 342652712.

217256243 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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 217256243 - 2² = 217256239 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (217256213) 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, 6389873 + ... + 6389906.

It is an arithmetic number, because the mean of its divisors is an integer number (57509010).

Almost surely, 2^217256243 is an apocalyptic number.

217256243 is a deficient number, since it is larger than the sum of its proper divisors (12779797).

217256243 is a wasteful number, since it uses less digits than its factorization.

217256243 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12779796.

The product of its digits is 20160, while the sum is 32.

The square root of 217256243 is about 14739.6147507321. The cubic root of 217256243 is about 601.1609402106.

The spelling of 217256243 in words is "two hundred seventeen million, two hundred fifty-six thousand, two hundred forty-three".