217928249 has 8 divisors (see below), whose sum is σ = 271702848. Its totient is φ = 169814160.

The previous prime is 217928239. The next prime is 217928267. The reversal of 217928249 is 942829712.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-217928249 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (217928239) 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, 1415042 + ... + 1415195.

It is an arithmetic number, because the mean of its divisors is an integer number (33962856).

Almost surely, 2^217928249 is an apocalyptic number.

It is an amenable number.

217928249 is a deficient number, since it is larger than the sum of its proper divisors (53774599).

217928249 is a wasteful number, since it uses less digits than its factorization.

217928249 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2830255.

The product of its digits is 145152, while the sum is 44.

The square root of 217928249 is about 14762.3930648117. The cubic root of 217928249 is about 601.7801290850.

The spelling of 217928249 in words is "two hundred seventeen million, nine hundred twenty-eight thousand, two hundred forty-nine".