21044202021 has 24 divisors (see below), whose sum is σ = 31186378080. Its totient is φ = 13666949856.

The previous prime is 21044201987. The next prime is 21044202071. The reversal of 21044202021 is 12020244012.

21044202021 is a `hidden beast` number, since 21 + 0 + 442 + 0 + 202 + 1 = 666.

It is not a de Polignac number, because 21044202021 - 2¹¹ = 21044199973 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21044201985 and 21044202003.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21044202071) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 74935 + ... + 218411.

It is an arithmetic number, because the mean of its divisors is an integer number (1299432420).

Almost surely, 2^21044202021 is an apocalyptic number.

It is an amenable number.

21044202021 is a deficient number, since it is larger than the sum of its proper divisors (10142176059).

21044202021 is a wasteful number, since it uses less digits than its factorization.

21044202021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 143905 (or 143902 counting only the distinct ones).

The product of its (nonzero) digits is 256, while the sum is 18.

Adding to 21044202021 its reverse (12020244012), we get a palindrome (33064446033).

The spelling of 21044202021 in words is "twenty-one billion, forty-four million, two hundred two thousand, twenty-one".