216220665 has 32 divisors (see below), whose sum is σ = 376732800. Its totient is φ = 105477120.

The previous prime is 216220601. The next prime is 216220717. The reversal of 216220665 is 566022612.

It is not a de Polignac number, because 216220665 - 2⁶ = 216220601 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 4816 + ... + 21345.

It is an arithmetic number, because the mean of its divisors is an integer number (11772900).

Almost surely, 2^216220665 is an apocalyptic number.

It is an amenable number.

216220665 is a deficient number, since it is larger than the sum of its proper divisors (160512135).

216220665 is a wasteful number, since it uses less digits than its factorization.

216220665 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 26217.

The product of its (nonzero) digits is 8640, while the sum is 30.

The square root of 216220665 is about 14704.4437161016. The cubic root of 216220665 is about 600.2042499065.

The spelling of 216220665 in words is "two hundred sixteen million, two hundred twenty thousand, six hundred sixty-five".