221696 has 20 divisors (see below), whose sum is σ = 443982. Its totient is φ = 110592.

The previous prime is 221677. The next prime is 221707. The reversal of 221696 is 696122.

It can be written as a sum of positive squares in only one way, i.e., 215296 + 6400 = 464^2 + 80^2 .

It is a nialpdrome in base 8.

It is a congruent number.

It is an unprimeable number.

221696 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a pernicious number, because its binary representation contains a prime number (5) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 296 + ... + 728.

2²²¹⁶⁹⁶ 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 221696, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (221991).

221696 is an abundant number, since it is smaller than the sum of its proper divisors (222286).

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

221696 is an frugal number, since it uses more digits than its factorization.

221696 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 451 (or 435 counting only the distinct ones).

The product of its digits is 1296, while the sum is 26.

The square root of 221696 is about 470.8460470260. The cubic root of 221696 is about 60.5228381778.

The spelling of 221696 in words is "two hundred twenty-one thousand, six hundred ninety-six".