21000222021 has 4 divisors (see below), whose sum is σ = 28000296032. Its totient is φ = 14000148012.

The previous prime is 21000222007. The next prime is 21000222071. The reversal of 21000222021 is 12022200012.

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 not a de Polignac number, because 21000222021 - 2⁵ = 21000221989 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21000221988 and 21000222006.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21000222071) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3500037001 + ... + 3500037006.

It is an arithmetic number, because the mean of its divisors is an integer number (7000074008).

Almost surely, 2^21000222021 is an apocalyptic number.

It is an amenable number.

21000222021 is a deficient number, since it is larger than the sum of its proper divisors (7000074011).

21000222021 is an equidigital number, since it uses as much as digits as its factorization.

21000222021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7000074010.

The product of its (nonzero) digits is 32, while the sum is 12.

Adding to 21000222021 its reverse (12022200012), we get a palindrome (33022422033).

The spelling of 21000222021 in words is "twenty-one billion, two hundred twenty-two thousand, twenty-one".