221123123 has 4 divisors (see below), whose sum is σ = 238132608. Its totient is φ = 204113640.

The previous prime is 221123117. The next prime is 221123143. The reversal of 221123123 is 321321122.

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

It is a cyclic number.

It is not a de Polignac number, because 221123123 - 2¹⁸ = 220860979 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (221123113) 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, 8504723 + ... + 8504748.

It is an arithmetic number, because the mean of its divisors is an integer number (59533152).

Almost surely, 2^221123123 is an apocalyptic number.

221123123 is a deficient number, since it is larger than the sum of its proper divisors (17009485).

221123123 is a wasteful number, since it uses less digits than its factorization.

221123123 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17009484.

The product of its digits is 144, while the sum is 17.

The square root of 221123123 is about 14870.2092453334. The cubic root of 221123123 is about 604.7066154863.

Adding to 221123123 its reverse (321321122), we get a palindrome (542444245).

The spelling of 221123123 in words is "two hundred twenty-one million, one hundred twenty-three thousand, one hundred twenty-three".