21222223021 has 4 divisors (see below), whose sum is σ = 21227266944. Its totient is φ = 21217179100.

The previous prime is 21222223019. The next prime is 21222223069. The reversal of 21222223021 is 12032222212.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21222223021 - 2¹ = 21222223019 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21222223021.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21222221021) 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, 2515645 + ... + 2524066.

It is an arithmetic number, because the mean of its divisors is an integer number (5306816736).

Almost surely, 2^21222223021 is an apocalyptic number.

It is an amenable number.

21222223021 is a deficient number, since it is larger than the sum of its proper divisors (5043923).

21222223021 is an equidigital number, since it uses as much as digits as its factorization.

21222223021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5043922.

The product of its (nonzero) digits is 384, while the sum is 19.

Adding to 21222223021 its reverse (12032222212), we get a palindrome (33254445233).

The spelling of 21222223021 in words is "twenty-one billion, two hundred twenty-two million, two hundred twenty-three thousand, twenty-one".