21220220021 has 64 divisors (see below), whose sum is σ = 29200711680. Its totient is φ = 14885717760.

The previous prime is 21220220017. The next prime is 21220220023. The reversal of 21220220021 is 12002202212.

It is a cyclic number.

It is not a de Polignac number, because 21220220021 - 2² = 21220220017 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21220219978 and 21220220005.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21220220023) 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 63 ways as a sum of consecutive naturals, for example, 17265635 + ... + 17266863.

It is an arithmetic number, because the mean of its divisors is an integer number (456261120).

Almost surely, 2^21220220021 is an apocalyptic number.

It is an amenable number.

21220220021 is a deficient number, since it is larger than the sum of its proper divisors (7980491659).

21220220021 is a wasteful number, since it uses less digits than its factorization.

21220220021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1674.

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

Adding to 21220220021 its reverse (12002202212), we get a palindrome (33222422233).

The spelling of 21220220021 in words is "twenty-one billion, two hundred twenty million, two hundred twenty thousand, twenty-one".