217505713 has 4 divisors (see below), whose sum is σ = 225005940. Its totient is φ = 210005488.

The previous prime is 217505689. The next prime is 217505737. The reversal of 217505713 is 317505712.

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

It is an interprime number because it is at equal distance from previous prime (217505689) and next prime (217505737).

It can be written as a sum of positive squares in 2 ways, for example, as 114746944 + 102758769 = 10712^2 + 10137^2 .

It is a cyclic number.

It is not a de Polignac number, because 217505713 - 2¹³ = 217497521 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (217505753) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3750070 + ... + 3750127.

It is an arithmetic number, because the mean of its divisors is an integer number (56251485).

Almost surely, 2^217505713 is an apocalyptic number.

It is an amenable number.

217505713 is a deficient number, since it is larger than the sum of its proper divisors (7500227).

217505713 is an equidigital number, since it uses as much as digits as its factorization.

217505713 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7500226.

The product of its (nonzero) digits is 7350, while the sum is 31.

The square root of 217505713 is about 14748.0748913206. The cubic root of 217505713 is about 601.3909516345.

Subtracting 217505713 from its reverse (317505712), we obtain a palindrome (99999999).

The spelling of 217505713 in words is "two hundred seventeen million, five hundred five thousand, seven hundred thirteen".