216641808 has 120 divisors (see below), whose sum is σ = 632345688. Its totient is φ = 69175296.

The previous prime is 216641797. The next prime is 216641809. The reversal of 216641808 is 808146612.

216641808 is a `hidden beast` number, since 2 + 1 + 6 + 641 + 8 + 0 + 8 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 34715664 + 181926144 = 5892^2 + 13488^2 .

It is a Harshad number since it is a multiple of its sum of digits (36).

It is not an unprimeable number, because it can be changed into a prime (216641809) 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, 388666 + ... + 389222.

Almost surely, 2^216641808 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 216641808, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (316172844).

216641808 is an abundant number, since it is smaller than the sum of its proper divisors (415703880).

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

216641808 is a wasteful number, since it uses less digits than its factorization.

216641808 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 681 (or 672 counting only the distinct ones).

The product of its (nonzero) digits is 18432, while the sum is 36.

The square root of 216641808 is about 14718.7570127372. The cubic root of 216641808 is about 600.5936790482.

The spelling of 216641808 in words is "two hundred sixteen million, six hundred forty-one thousand, eight hundred eight".