215728 has 20 divisors (see below), whose sum is σ = 425320. Its totient is φ = 105984.

The previous prime is 215723. The next prime is 215737. The reversal of 215728 is 827512.

It is not an unprimeable number, because it can be changed into a prime (215723) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1483 + ... + 1621.

It is an arithmetic number, because the mean of its divisors is an integer number (21266).

2²¹⁵⁷²⁸ is an apocalyptic number.

It is an amenable number.

215728 is a deficient number, since it is larger than the sum of its proper divisors (209592).

215728 is a wasteful number, since it uses less digits than its factorization.

215728 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 244 (or 238 counting only the distinct ones).

The product of its digits is 1120, while the sum is 25.

The square root of 215728 is about 464.4652839556. The cubic root of 215728 is about 59.9748042359.

It can be divided in two parts, 215 and 728, that multiplied together give a triangular number (156520 = T₅₅₉).

The spelling of 215728 in words is "two hundred fifteen thousand, seven hundred twenty-eight".