217704138 has 16 divisors (see below), whose sum is σ = 436830240. Its totient is φ = 72331056.

The previous prime is 217704133. The next prime is 217704161. The reversal of 217704138 is 831407712.

It is a happy number.

It is a junction number, because it is equal to n+sod(n) for n = 217704099 and 217704108.

It is not an unprimeable number, because it can be changed into a prime (217704133) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 57253 + ... + 60936.

It is an arithmetic number, because the mean of its divisors is an integer number (27301890).

Almost surely, 2^217704138 is an apocalyptic number.

217704138 is an abundant number, since it is smaller than the sum of its proper divisors (219126102).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

217704138 is a wasteful number, since it uses less digits than its factorization.

217704138 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 118501.

The product of its (nonzero) digits is 9408, while the sum is 33.

The square root of 217704138 is about 14754.8005069537. The cubic root of 217704138 is about 601.5737740054.

The spelling of 217704138 in words is "two hundred seventeen million, seven hundred four thousand, one hundred thirty-eight".