217207081 has 24 divisors (see below), whose sum is σ = 271952640. Its totient is φ = 169842816.

The previous prime is 217207063. The next prime is 217207127. The reversal of 217207081 is 180702712.

It is not a de Polignac number, because 217207081 - 2¹³ = 217198889 is a prime.

It is a super-2 number, since 2×217207081² = 94357832073081122, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (217207051) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 104256 + ... + 106318.

It is an arithmetic number, because the mean of its divisors is an integer number (11331360).

Almost surely, 2^217207081 is an apocalyptic number.

It is an amenable number.

217207081 is a deficient number, since it is larger than the sum of its proper divisors (54745559).

217207081 is a wasteful number, since it uses less digits than its factorization.

217207081 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2185 (or 2172 counting only the distinct ones).

The product of its (nonzero) digits is 1568, while the sum is 28.

The square root of 217207081 is about 14737.9469737138. The cubic root of 217207081 is about 601.1155920643.

Adding to 217207081 its reverse (180702712), we get a palindrome (397909793).

The spelling of 217207081 in words is "two hundred seventeen million, two hundred seven thousand, eighty-one".