21042224021 has 32 divisors (see below), whose sum is σ = 26526044160. Its totient is φ = 16245883584.

The previous prime is 21042223973. The next prime is 21042224023. The reversal of 21042224021 is 12042224012.

It is not a de Polignac number, because 21042224021 - 2²² = 21038029717 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21042223984 and 21042224002.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21042224023) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 5566310 + ... + 5570088.

It is an arithmetic number, because the mean of its divisors is an integer number (828938880).

Almost surely, 2^21042224021 is an apocalyptic number.

It is an amenable number.

21042224021 is a deficient number, since it is larger than the sum of its proper divisors (5483820139).

21042224021 is a wasteful number, since it uses less digits than its factorization.

21042224021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5265.

The product of its (nonzero) digits is 512, while the sum is 20.

Adding to 21042224021 its reverse (12042224012), we get a palindrome (33084448033).

Subtracting from 21042224021 its reverse (12042224012), we obtain a palindrome (9000000009).

The spelling of 21042224021 in words is "twenty-one billion, forty-two million, two hundred twenty-four thousand, twenty-one".