217422081 has 6 divisors (see below), whose sum is σ = 314054130. Its totient is φ = 144948048.

The previous prime is 217422043. The next prime is 217422097. The reversal of 217422081 is 180224712.

It can be written as a sum of positive squares in only one way, i.e., 217415025 + 7056 = 14745^2 + 84^2 .

It is not a de Polignac number, because 217422081 - 2⁶ = 217422017 is a prime.

It is a super-2 number, since 2×217422081² = 94544722612741122, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (217422041) 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 5 ways as a sum of consecutive naturals, for example, 12078996 + ... + 12079013.

It is an arithmetic number, because the mean of its divisors is an integer number (52342355).

Almost surely, 2^217422081 is an apocalyptic number.

It is an amenable number.

217422081 is a deficient number, since it is larger than the sum of its proper divisors (96632049).

217422081 is a wasteful number, since it uses less digits than its factorization.

217422081 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 24158015 (or 24158012 counting only the distinct ones).

The product of its (nonzero) digits is 1792, while the sum is 27.

The square root of 217422081 is about 14745.2392656071. The cubic root of 217422081 is about 601.3138625088.

Adding to 217422081 its reverse (180224712), we get a palindrome (397646793).

The spelling of 217422081 in words is "two hundred seventeen million, four hundred twenty-two thousand, eighty-one".