217081231 has 8 divisors (see below), whose sum is σ = 219532784. Its totient is φ = 214643520.

The previous prime is 217081223. The next prime is 217081259. The reversal of 217081231 is 132180712.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 217081231 - 2³ = 217081223 is a prime.

It is a super-4 number, since 4×217081231⁴ (a number of 34 digits) contains 4444 as substring. Note that it is a super-d number also for d = 2.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 217081196 and 217081205.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (217081031) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 29851 + ... + 36403.

It is an arithmetic number, because the mean of its divisors is an integer number (27441598).

Almost surely, 2^217081231 is an apocalyptic number.

217081231 is a deficient number, since it is larger than the sum of its proper divisors (2451553).

217081231 is a wasteful number, since it uses less digits than its factorization.

217081231 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6921.

The product of its (nonzero) digits is 672, while the sum is 25.

The square root of 217081231 is about 14733.6767644740. The cubic root of 217081231 is about 600.9994739766. Note that the first 3 decimals are identical.

The spelling of 217081231 in words is "two hundred seventeen million, eighty-one thousand, two hundred thirty-one".