217384400081 has 2 divisors, whose sum is σ = 217384400082. Its totient is φ = 217384400080.

The previous prime is 217384400069. The next prime is 217384400117. The reversal of 217384400081 is 180004483712.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 111395737600 + 105988662481 = 333760^2 + 325559^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-217384400081 is a prime.

It is a super-2 number, since 2×217384400081² (a number of 23 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (217384400011) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 108692200040 + 108692200041.

It is an arithmetic number, because the mean of its divisors is an integer number (108692200041).

Almost surely, 2^217384400081 is an apocalyptic number.

It is an amenable number.

217384400081 is a deficient number, since it is larger than the sum of its proper divisors (1).

217384400081 is an equidigital number, since it uses as much as digits as its factorization.

217384400081 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 43008, while the sum is 38.

Adding to 217384400081 its reverse (180004483712), we get a palindrome (397388883793).

The spelling of 217384400081 in words is "two hundred seventeen billion, three hundred eighty-four million, four hundred thousand, eighty-one".