223991 has 4 divisors (see below), whose sum is σ = 235800. Its totient is φ = 212184.

The previous prime is 223969. The next prime is 223999. The reversal of 223991 is 199322.

223991 is nontrivially palindromic in base 14.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 199322 = 2 ⋅99661.

It is a cyclic number.

It is not a de Polignac number, because 223991 - 2¹⁰ = 222967 is a prime.

It is a Duffinian number.

It is a plaindrome in base 6.

It is a zygodrome in base 6.

It is a self number, because there is not a number n which added to its sum of digits gives 223991.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (223999) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5876 + ... + 5913.

It is an arithmetic number, because the mean of its divisors is an integer number (58950).

2²²³⁹⁹¹ is an apocalyptic number.

223991 is a deficient number, since it is larger than the sum of its proper divisors (11809).

223991 is a wasteful number, since it uses less digits than its factorization.

223991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11808.

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

The square root of 223991 is about 473.2768745671. The cubic root of 223991 is about 60.7309660546.

The spelling of 223991 in words is "two hundred twenty-three thousand, nine hundred ninety-one".