221212123 has 8 divisors (see below), whose sum is σ = 242102016. Its totient is φ = 200452200.

The previous prime is 221212111. The next prime is 221212129. The reversal of 221212123 is 321212122.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 221212123 - 2⁹ = 221211611 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 221212097 and 221212106.

It is not an unprimeable number, because it can be changed into a prime (221212129) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 28911 + ... + 35752.

It is an arithmetic number, because the mean of its divisors is an integer number (30262752).

Almost surely, 2^221212123 is an apocalyptic number.

221212123 is a deficient number, since it is larger than the sum of its proper divisors (20889893).

221212123 is a wasteful number, since it uses less digits than its factorization.

221212123 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 64985.

The product of its digits is 96, while the sum is 16.

The square root of 221212123 is about 14873.2015047198. The cubic root of 221212123 is about 604.7877341999.

Adding to 221212123 its reverse (321212122), we get a palindrome (542424245).

Subtracting 221212123 from its reverse (321212122), we obtain a palindrome (99999999).

The spelling of 221212123 in words is "two hundred twenty-one million, two hundred twelve thousand, one hundred twenty-three".