216820784 has 20 divisors (see below), whose sum is σ = 423811416. Its totient is φ = 107450112.

The previous prime is 216820781. The next prime is 216820819. The reversal of 216820784 is 487028612.

It is a super-2 number, since 2×216820784² = 94022504748749312, which contains 22 as substring.

It is a Smith number, since the sum of its digits (38) coincides with the sum of the digits of its prime factors.

It is not an unprimeable number, because it can be changed into a prime (216820781) by changing a digit.

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 in 3 ways as a sum of consecutive naturals, for example, 58154 + ... + 61769.

Almost surely, 2^216820784 is an apocalyptic number.

It is an amenable number.

216820784 is a deficient number, since it is larger than the sum of its proper divisors (206990632).

216820784 is a wasteful number, since it uses less digits than its factorization.

216820784 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 120044 (or 120038 counting only the distinct ones).

The product of its (nonzero) digits is 43008, while the sum is 38.

The square root of 216820784 is about 14724.8356187769. The cubic root of 216820784 is about 600.7590245831.

The spelling of 216820784 in words is "two hundred sixteen million, eight hundred twenty thousand, seven hundred eighty-four".