221993 has 4 divisors (see below), whose sum is σ = 225108. Its totient is φ = 218880.

The previous prime is 221989. The next prime is 221999. The reversal of 221993 is 399122.

221993 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 183184 + 38809 = 428^2 + 197^2 .

It is a cyclic number.

It is not a de Polignac number, because 221993 - 2² = 221989 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 221993.

It is not an unprimeable number, because it can be changed into a prime (221999) 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, 1448 + ... + 1593.

It is an arithmetic number, because the mean of its divisors is an integer number (56277).

2²²¹⁹⁹³ is an apocalyptic number.

It is an amenable number.

221993 is a deficient number, since it is larger than the sum of its proper divisors (3115).

221993 is an equidigital number, since it uses as much as digits as its factorization.

221993 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3114.

The product of its digits is 972, while the sum is 26.

The square root of 221993 is about 471.1613311807. The cubic root of 221993 is about 60.5498530419.

It can be divided in two parts, 221 and 993, that multiplied together give a triangular number (219453 = T₆₆₂).

The spelling of 221993 in words is "two hundred twenty-one thousand, nine hundred ninety-three".