221985 has 12 divisors (see below), whose sum is σ = 384852. Its totient is φ = 118368.

The previous prime is 221957. The next prime is 221987. The reversal of 221985 is 589122.

It can be written as a sum of positive squares in 2 ways, for example, as 74529 + 147456 = 273^2 + 384^2 .

It is not a de Polignac number, because 221985 - 2⁵ = 221953 is a prime.

It is a hoax number, since the sum of its digits (27) coincides with the sum of the digits of its distinct prime factors.

It is not an unprimeable number, because it can be changed into a prime (221987) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 2422 + ... + 2511.

It is an arithmetic number, because the mean of its divisors is an integer number (32071).

2²²¹⁹⁸⁵ is an apocalyptic number.

It is an amenable number.

221985 is a deficient number, since it is larger than the sum of its proper divisors (162867).

221985 is a wasteful number, since it uses less digits than its factorization.

221985 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4944 (or 4941 counting only the distinct ones).

The product of its digits is 1440, while the sum is 27.

The square root of 221985 is about 471.1528414432. The cubic root of 221985 is about 60.5491256846.

It can be divided in two parts, 2219 and 85, that added together give a square (2304 = 48²).

The spelling of 221985 in words is "two hundred twenty-one thousand, nine hundred eighty-five".