216688857 has 48 divisors (see below), whose sum is σ = 370016640. Its totient is φ = 110373120.

The previous prime is 216688799. The next prime is 216688873. The reversal of 216688857 is 758886612.

It is not a de Polignac number, because 216688857 - 2¹⁰ = 216687833 is a prime.

It is not an unprimeable number, because it can be changed into a prime (216688457) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 133869 + ... + 135477.

It is an arithmetic number, because the mean of its divisors is an integer number (7708680).

Almost surely, 2^216688857 is an apocalyptic number.

It is an amenable number.

216688857 is a deficient number, since it is larger than the sum of its proper divisors (153327783).

216688857 is a wasteful number, since it uses less digits than its factorization.

216688857 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1694 (or 1683 counting only the distinct ones).

The product of its digits is 1290240, while the sum is 51.

The square root of 216688857 is about 14720.3551927255. The cubic root of 216688857 is about 600.6371537080.

The spelling of 216688857 in words is "two hundred sixteen million, six hundred eighty-eight thousand, eight hundred fifty-seven".