215685216 has 72 divisors (see below), whose sum is σ = 621817560. Its totient is φ = 70903296.

The previous prime is 215685163. The next prime is 215685221. The reversal of 215685216 is 612586512.

It is a tau number, because it is divible by the number of its divisors (72).

It is a super-2 number, since 2×215685216² = 93040224801933312, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 15895 + ... + 26153.

It is an arithmetic number, because the mean of its divisors is an integer number (8636355).

Almost surely, 2^215685216 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 215685216, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (310908780).

215685216 is an abundant number, since it is smaller than the sum of its proper divisors (406132344).

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

215685216 is a wasteful number, since it uses less digits than its factorization.

215685216 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10348 (or 10337 counting only the distinct ones).

The product of its digits is 28800, while the sum is 36.

The square root of 215685216 is about 14686.2253829907. The cubic root of 215685216 is about 599.7083916306.

The spelling of 215685216 in words is "two hundred fifteen million, six hundred eighty-five thousand, two hundred sixteen".