217121006 has 4 divisors (see below), whose sum is σ = 325681512. Its totient is φ = 108560502.

The previous prime is 217120987. The next prime is 217121011. The reversal of 217121006 is 600121712.

It is a semiprime because it is the product of two primes.

It is a congruent number.

It is an unprimeable number.

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 as a sum of consecutive naturals, namely, 54280250 + ... + 54280253.

It is an arithmetic number, because the mean of its divisors is an integer number (81420378).

Almost surely, 2^217121006 is an apocalyptic number.

217121006 is a deficient number, since it is larger than the sum of its proper divisors (108560506).

217121006 is a wasteful number, since it uses less digits than its factorization.

217121006 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 108560505.

The product of its (nonzero) digits is 168, while the sum is 20.

The square root of 217121006 is about 14735.0265015031. The cubic root of 217121006 is about 601.0361780468.

Adding to 217121006 its reverse (600121712), we get a palindrome (817242718).

The spelling of 217121006 in words is "two hundred seventeen million, one hundred twenty-one thousand, six".