21212122223 has 4 divisors (see below), whose sum is σ = 21213695880. Its totient is φ = 21210548568.

The previous prime is 21212122219. The next prime is 21212122229. The reversal of 21212122223 is 32222121212.

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 21212122223 - 2² = 21212122219 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21212122195 and 21212122204.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21212122229) 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 3 ways as a sum of consecutive naturals, for example, 766433 + ... + 793626.

It is an arithmetic number, because the mean of its divisors is an integer number (5303423970).

Almost surely, 2^21212122223 is an apocalyptic number.

21212122223 is a deficient number, since it is larger than the sum of its proper divisors (1573657).

21212122223 is a wasteful number, since it uses less digits than its factorization.

21212122223 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1573656.

The product of its digits is 384, while the sum is 20.

Adding to 21212122223 its reverse (32222121212), we get a palindrome (53434243435).

The spelling of 21212122223 in words is "twenty-one billion, two hundred twelve million, one hundred twenty-two thousand, two hundred twenty-three".