21220022021 has 4 divisors (see below), whose sum is σ = 23149114944. Its totient is φ = 19290929100.

The previous prime is 21220021987. The next prime is 21220022023. The reversal of 21220022021 is 12022002212.

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 21220022021 - 2³⁰ = 20146280197 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21220021987 and 21220022005.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21220022023) 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, 964546445 + ... + 964546466.

It is an arithmetic number, because the mean of its divisors is an integer number (5787278736).

Almost surely, 2^21220022021 is an apocalyptic number.

It is an amenable number.

21220022021 is a deficient number, since it is larger than the sum of its proper divisors (1929092923).

21220022021 is a wasteful number, since it uses less digits than its factorization.

21220022021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1929092922.

The product of its (nonzero) digits is 64, while the sum is 14.

Adding to 21220022021 its reverse (12022002212), we get a palindrome (33242024233).

The spelling of 21220022021 in words is "twenty-one billion, two hundred twenty million, twenty-two thousand, twenty-one".