21223212021 has 36 divisors (see below), whose sum is σ = 35295474240. Its totient is φ = 12185555760.

The previous prime is 21223212011. The next prime is 21223212037. The reversal of 21223212021 is 12021232212.

It is not a de Polignac number, because 21223212021 - 2²⁵ = 21189657589 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21223211985 and 21223212003.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21223212001) by changing a digit.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 261181 + ... + 332658.

It is an arithmetic number, because the mean of its divisors is an integer number (980429840).

Almost surely, 2^21223212021 is an apocalyptic number.

It is an amenable number.

21223212021 is a deficient number, since it is larger than the sum of its proper divisors (14072262219).

21223212021 is a wasteful number, since it uses less digits than its factorization.

21223212021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 593894 (or 593872 counting only the distinct ones).

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

Adding to 21223212021 its reverse (12021232212), we get a palindrome (33244444233).

The spelling of 21223212021 in words is "twenty-one billion, two hundred twenty-three million, two hundred twelve thousand, twenty-one".