217857023 has 4 divisors (see below), whose sum is σ = 230672160. Its totient is φ = 205041888.

The previous prime is 217857001. The next prime is 217857037. The reversal of 217857023 is 320758712.

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 217857023 - 2⁸ = 217856767 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 (217857043) 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, 6407543 + ... + 6407576.

It is an arithmetic number, because the mean of its divisors is an integer number (57668040).

Almost surely, 2^217857023 is an apocalyptic number.

217857023 is a deficient number, since it is larger than the sum of its proper divisors (12815137).

217857023 is a wasteful number, since it uses less digits than its factorization.

217857023 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12815136.

The product of its (nonzero) digits is 23520, while the sum is 35.

The square root of 217857023 is about 14759.9804539166. The cubic root of 217857023 is about 601.7145615383.

The spelling of 217857023 in words is "two hundred seventeen million, eight hundred fifty-seven thousand, twenty-three".