217210721116081 has 32 divisors (see below), whose sum is σ = 270878316134400. Its totient is φ = 169211273628480.

The previous prime is 217210721115961. The next prime is 217210721116087. The reversal of 217210721116081 is 180611127012712.

It is a cyclic number.

It is not a de Polignac number, because 217210721116081 - 2⁹ = 217210721115569 is a prime.

It is a super-2 number, since 2×217210721116081² (a number of 29 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (217210721116087) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 6053961300 + ... + 6053997178.

It is an arithmetic number, because the mean of its divisors is an integer number (8464947379200).

Almost surely, 2^{217210721116081} is an apocalyptic number.

It is an amenable number.

217210721116081 is a deficient number, since it is larger than the sum of its proper divisors (53667595018319).

217210721116081 is a wasteful number, since it uses less digits than its factorization.

217210721116081 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 54069.

The product of its (nonzero) digits is 18816, while the sum is 40.

Adding to 217210721116081 its reverse (180611127012712), we get a palindrome (397821848128793).

The spelling of 217210721116081 in words is "two hundred seventeen trillion, two hundred ten billion, seven hundred twenty-one million, one hundred sixteen thousand, eighty-one".