221680 has 40 divisors (see below), whose sum is σ = 549072. Its totient is φ = 82944.

The previous prime is 221677. The next prime is 221707. The reversal of 221680 is 86122.

It is a happy number.

221680 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a tau number, because it is divible by the number of its divisors (40).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1279 + ... + 1441.

2²²¹⁶⁸⁰ is an apocalyptic number.

221680 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 221680, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (274536).

221680 is an abundant number, since it is smaller than the sum of its proper divisors (327392).

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

221680 is a wasteful number, since it uses less digits than its factorization.

221680 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 193 (or 187 counting only the distinct ones).

The product of its (nonzero) digits is 192, while the sum is 19.

The square root of 221680 is about 470.8290560278. The cubic root of 221680 is about 60.5213821469.

The spelling of 221680 in words is "two hundred twenty-one thousand, six hundred eighty".