217800013 has 2 divisors, whose sum is σ = 217800014. Its totient is φ = 217800012.

The previous prime is 217799993. The next prime is 217800029. The reversal of 217800013 is 310008712.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 201129124 + 16670889 = 14182^2 + 4083^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-217800013 is a prime.

It is equal to p_12008047 and since 217800013 and 12008047 have the same sum of digits, it is a Honaker prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (217800043) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 108900006 + 108900007.

It is an arithmetic number, because the mean of its divisors is an integer number (108900007).

Almost surely, 2^217800013 is an apocalyptic number.

It is an amenable number.

217800013 is a deficient number, since it is larger than the sum of its proper divisors (1).

217800013 is an equidigital number, since it uses as much as digits as its factorization.

217800013 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 336, while the sum is 22.

The square root of 217800013 is about 14758.0490919362. The cubic root of 217800013 is about 601.6620703228.

Adding to 217800013 its reverse (310008712), we get a palindrome (527808725).

The spelling of 217800013 in words is "two hundred seventeen million, eight hundred thousand, thirteen".