217155121 has 8 divisors (see below), whose sum is σ = 229466880. Its totient is φ = 205082592.

The previous prime is 217155119. The next prime is 217155131. The reversal of 217155121 is 121551712.

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 217155121 - 2¹ = 217155119 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (217155131) 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 7 ways as a sum of consecutive naturals, for example, 57940 + ... + 61573.

It is an arithmetic number, because the mean of its divisors is an integer number (28683360).

Almost surely, 2^217155121 is an apocalyptic number.

It is an amenable number.

217155121 is a deficient number, since it is larger than the sum of its proper divisors (12311759).

217155121 is a wasteful number, since it uses less digits than its factorization.

217155121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 119615.

The product of its digits is 700, while the sum is 25.

The square root of 217155121 is about 14736.1840718688. The cubic root of 217155121 is about 601.0676555407.

The spelling of 217155121 in words is "two hundred seventeen million, one hundred fifty-five thousand, one hundred twenty-one".