21021212223 has 24 divisors (see below), whose sum is σ = 34266557520. Its totient is φ = 12300812160.

The previous prime is 21021212221. The next prime is 21021212231. The reversal of 21021212223 is 32221212012.

21021212223 is a `hidden beast` number, since 210 + 21 + 212 + 223 = 666.

It is not a de Polignac number, because 21021212223 - 2¹ = 21021212221 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21021212196 and 21021212205.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21021212221) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 3658086 + ... + 3663827.

It is an arithmetic number, because the mean of its divisors is an integer number (1427773230).

Almost surely, 2^21021212223 is an apocalyptic number.

21021212223 is a deficient number, since it is larger than the sum of its proper divisors (13245345297).

21021212223 is a wasteful number, since it uses less digits than its factorization.

21021212223 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7321959 (or 7321956 counting only the distinct ones).

The product of its (nonzero) digits is 192, while the sum is 18.

Adding to 21021212223 its reverse (32221212012), we get a palindrome (53242424235).

The spelling of 21021212223 in words is "twenty-one billion, twenty-one million, two hundred twelve thousand, two hundred twenty-three".