215688 has 64 divisors (see below), whose sum is σ = 633600. Its totient is φ = 60480.

The previous prime is 215687. The next prime is 215689. The reversal of 215688 is 886512.

It is an interprime number because it is at equal distance from previous prime (215687) and next prime (215689).

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 215688.

It is not an unprimeable number, because it can be changed into a prime (215681) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 4995 + ... + 5037.

It is an arithmetic number, because the mean of its divisors is an integer number (9900).

2²¹⁵⁶⁸⁸ 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 215688, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (316800).

215688 is an abundant number, since it is smaller than the sum of its proper divisors (417912).

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

215688 is a wasteful number, since it uses less digits than its factorization.

215688 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 82 (or 78 counting only the distinct ones).

The product of its digits is 3840, while the sum is 30.

The square root of 215688 is about 464.4222216906. The cubic root of 215688 is about 59.9710971905.

It can be divided in two parts, 215 and 688, that added together give a triangular number (903 = T₄₂).

The spelling of 215688 in words is "two hundred fifteen thousand, six hundred eighty-eight".