216920665 has 16 divisors (see below), whose sum is σ = 280659456. Its totient is φ = 159998400.

The previous prime is 216920657. The next prime is 216920707. The reversal of 216920665 is 566029612.

It is not a de Polignac number, because 216920665 - 2³ = 216920657 is a prime.

It is a Duffinian number.

It is an unprimeable number.

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 15 ways as a sum of consecutive naturals, for example, 78660 + ... + 81370.

It is an arithmetic number, because the mean of its divisors is an integer number (17541216).

Almost surely, 2^216920665 is an apocalyptic number.

It is an amenable number.

216920665 is a deficient number, since it is larger than the sum of its proper divisors (63738791).

216920665 is a wasteful number, since it uses less digits than its factorization.

216920665 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3960.

The product of its (nonzero) digits is 38880, while the sum is 37.

The square root of 216920665 is about 14728.2268111270. The cubic root of 216920665 is about 600.8512592841.

The spelling of 216920665 in words is "two hundred sixteen million, nine hundred twenty thousand, six hundred sixty-five".