216640312 has 96 divisors (see below), whose sum is σ = 496903680. Its totient is φ = 86708160.

The previous prime is 216640301. The next prime is 216640313. The reversal of 216640312 is 213046612.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (216640313) 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, 2103253 + ... + 2103355.

It is an arithmetic number, because the mean of its divisors is an integer number (5176080).

Almost surely, 2^216640312 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 216640312, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (248451840).

216640312 is an abundant number, since it is smaller than the sum of its proper divisors (280263368).

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

216640312 is a wasteful number, since it uses less digits than its factorization.

216640312 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 233 (or 206 counting only the distinct ones).

The product of its (nonzero) digits is 1728, while the sum is 25.

The square root of 216640312 is about 14718.7061931408. The cubic root of 216640312 is about 600.5922965970.

Adding to 216640312 its reverse (213046612), we get a palindrome (429686924).

The spelling of 216640312 in words is "two hundred sixteen million, six hundred forty thousand, three hundred twelve".