215681312 has 192 divisors, whose sum is σ = 592220160. Its totient is φ = 74649600.

The previous prime is 215681287. The next prime is 215681317. The reversal of 215681312 is 213186512.

It is not an unprimeable number, because it can be changed into a prime (215681317) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 795737 + ... + 796007.

It is an arithmetic number, because the mean of its divisors is an integer number (3084480).

Almost surely, 2^215681312 is an apocalyptic number.

215681312 is a gapful number since it is divisible by the number (22) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 215681312, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (296110080).

215681312 is an abundant number, since it is smaller than the sum of its proper divisors (376538848).

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

215681312 is a wasteful number, since it uses less digits than its factorization.

215681312 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 335 (or 327 counting only the distinct ones).

The product of its digits is 2880, while the sum is 29.

The square root of 215681312 is about 14686.0924687270. The cubic root of 215681312 is about 599.7047732776.

The spelling of 215681312 in words is "two hundred fifteen million, six hundred eighty-one thousand, three hundred twelve".