216643128 has 96 divisors (see below), whose sum is σ = 605744640. Its totient is φ = 64471680.

The previous prime is 216643127. The next prime is 216643129. The reversal of 216643128 is 821346612.

It is an interprime number because it is at equal distance from previous prime (216643127) and next prime (216643129).

It is a nude number because it is divisible by every one of its digits.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (216643127) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 124875 + ... + 126597.

It is an arithmetic number, because the mean of its divisors is an integer number (6309840).

Almost surely, 2^216643128 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 216643128, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (302872320).

216643128 is an abundant number, since it is smaller than the sum of its proper divisors (389101512).

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

216643128 is a wasteful number, since it uses less digits than its factorization.

216643128 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1789 (or 1772 counting only the distinct ones).

The product of its digits is 13824, while the sum is 33.

The square root of 216643128 is about 14718.8018534118. The cubic root of 216643128 is about 600.5948988529.

The spelling of 216643128 in words is "two hundred sixteen million, six hundred forty-three thousand, one hundred twenty-eight".