216409284 has 108 divisors (see below), whose sum is σ = 685368684. Its totient is φ = 57068928.

The previous prime is 216409279. The next prime is 216409289. The reversal of 216409284 is 482904612.

216409284 is a `hidden beast` number, since 2 + 1 + 640 + 9 + 2 + 8 + 4 = 666.

It is an interprime number because it is at equal distance from previous prime (216409279) and next prime (216409289).

It can be written as a sum of positive squares in 2 ways, for example, as 74132100 + 142277184 = 8610^2 + 11928^2 .

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 (216409289) by changing a digit.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 18214 + ... + 27650.

Almost surely, 2^216409284 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 216409284, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (342684342).

216409284 is an abundant number, since it is smaller than the sum of its proper divisors (468959400).

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

216409284 is a wasteful number, since it uses less digits than its factorization.

216409284 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9474 (or 9462 counting only the distinct ones).

The product of its (nonzero) digits is 27648, while the sum is 36.

The square root of 216409284 is about 14710.8559914099. The cubic root of 216409284 is about 600.3787275588.

The spelling of 216409284 in words is "two hundred sixteen million, four hundred nine thousand, two hundred eighty-four".