223212121 has 16 divisors (see below), whose sum is σ = 253886976. Its totient is φ = 194400000.

The previous prime is 223212113. The next prime is 223212127. The reversal of 223212121 is 121212322.

It is a happy number.

It is a 5-Lehmer number, since φ(223212121) divides (223212121-1)⁵.

It is a cyclic number.

It is not a de Polignac number, because 223212121 - 2³ = 223212113 is a prime.

It is a super-3 number, since 3×223212121³ (a number of 26 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 223212095 and 223212104.

It is not an unprimeable number, because it can be changed into a prime (223212127) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 31201 + ... + 37681.

It is an arithmetic number, because the mean of its divisors is an integer number (15867936).

Almost surely, 2^223212121 is an apocalyptic number.

It is an amenable number.

223212121 is a deficient number, since it is larger than the sum of its proper divisors (30674855).

223212121 is a wasteful number, since it uses less digits than its factorization.

223212121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6624.

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

The square root of 223212121 is about 14940.2851713078. The cubic root of 223212121 is about 606.6049148527.

Adding to 223212121 its reverse (121212322), we get a palindrome (344424443).

It can be divided in two parts, 22321 and 2121, that added together give a palindrome (24442).

The spelling of 223212121 in words is "two hundred twenty-three million, two hundred twelve thousand, one hundred twenty-one".