216655989 has 8 divisors (see below), whose sum is σ = 315136032. Its totient is φ = 131306640.

The previous prime is 216655987. The next prime is 216655991. The reversal of 216655989 is 989556612.

It is an interprime number because it is at equal distance from previous prime (216655987) and next prime (216655991).

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

It is not a de Polignac number, because 216655989 - 2¹ = 216655987 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (216655987) 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, 3282634 + ... + 3282699.

It is an arithmetic number, because the mean of its divisors is an integer number (39392004).

Almost surely, 2^216655989 is an apocalyptic number.

It is an amenable number.

216655989 is a deficient number, since it is larger than the sum of its proper divisors (98480043).

216655989 is a wasteful number, since it uses less digits than its factorization.

216655989 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6565347.

The product of its digits is 1166400, while the sum is 51.

The square root of 216655989 is about 14719.2387371087. The cubic root of 216655989 is about 600.6067833719.

The spelling of 216655989 in words is "two hundred sixteen million, six hundred fifty-five thousand, nine hundred eighty-nine".