217115906 has 16 divisors (see below), whose sum is σ = 388381824. Its totient is φ = 89003904.

The previous prime is 217115903. The next prime is 217115911. The reversal of 217115906 is 609511712.

217115906 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It is not an unprimeable number, because it can be changed into a prime (217115903) 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, 336815 + ... + 337458.

It is an arithmetic number, because the mean of its divisors is an integer number (24273864).

Almost surely, 2^217115906 is an apocalyptic number.

217115906 is a deficient number, since it is larger than the sum of its proper divisors (171265918).

217115906 is a wasteful number, since it uses less digits than its factorization.

217115906 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 674305.

The product of its (nonzero) digits is 3780, while the sum is 32.

The square root of 217115906 is about 14734.8534434517. The cubic root of 217115906 is about 601.0314720558.

The spelling of 217115906 in words is "two hundred seventeen million, one hundred fifteen thousand, nine hundred six".