215297856 has 84 divisors (see below), whose sum is σ = 638441700. Its totient is φ = 69285888.

The previous prime is 215297851. The next prime is 215297881. The reversal of 215297856 is 658792512.

215297856 is a `hidden beast` number, since 2 + 1 + 529 + 78 + 56 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 127238400 + 88059456 = 11280^2 + 9384^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (215297851) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 10260 + ... + 23148.

Almost surely, 2^215297856 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 215297856, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (319220850).

215297856 is an abundant number, since it is smaller than the sum of its proper divisors (423143844).

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

215297856 is a wasteful number, since it uses less digits than its factorization.

215297856 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12936 (or 12923 counting only the distinct ones).

The product of its digits is 302400, while the sum is 45.

The square root of 215297856 is about 14673.0315885982. The cubic root of 215297856 is about 599.3491609361.

It can be divided in two parts, 215297 and 856, that added together give a triangular number (216153 = T₆₅₇).

The spelling of 215297856 in words is "two hundred fifteen million, two hundred ninety-seven thousand, eight hundred fifty-six".