216643386 has 16 divisors (see below), whose sum is σ = 437263200. Its totient is φ = 71551728.

The previous prime is 216643379. The next prime is 216643387. The reversal of 216643386 is 683346612.

It is not an unprimeable number, because it can be changed into a prime (216643387) by changing a digit.

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 7 ways as a sum of consecutive naturals, for example, 164976 + ... + 166283.

It is an arithmetic number, because the mean of its divisors is an integer number (27328950).

Almost surely, 2^216643386 is an apocalyptic number.

216643386 is an abundant number, since it is smaller than the sum of its proper divisors (220619814).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

216643386 is a wasteful number, since it uses less digits than its factorization.

216643386 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 331373.

The product of its digits is 124416, while the sum is 39.

The square root of 216643386 is about 14718.8106177096. The cubic root of 216643386 is about 600.5951372687.

Adding to 216643386 its reverse (683346612), we get a palindrome (899989998).

The spelling of 216643386 in words is "two hundred sixteen million, six hundred forty-three thousand, three hundred eighty-six".