216643648 has 112 divisors (see below), whose sum is σ = 501182640. Its totient is φ = 92332032.

The previous prime is 216643627. The next prime is 216643657. The reversal of 216643648 is 846346612.

It can be written as a sum of positive squares in 8 ways, for example, as 200704 + 216442944 = 448^2 + 14712^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 216643648.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 4087590 + ... + 4087642.

It is an arithmetic number, because the mean of its divisors is an integer number (4474845).

Almost surely, 2^216643648 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 216643648, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (250591320).

216643648 is an abundant number, since it is smaller than the sum of its proper divisors (284538992).

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

216643648 is an equidigital number, since it uses as much as digits as its factorization.

216643648 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 129 (or 85 counting only the distinct ones).

The product of its digits is 165888, while the sum is 40.

The square root of 216643648 is about 14718.8195178825. The cubic root of 216643648 is about 600.5953793806.

The spelling of 216643648 in words is "two hundred sixteen million, six hundred forty-three thousand, six hundred forty-eight".