21300442021 has 4 divisors (see below), whose sum is σ = 21592228972. Its totient is φ = 21008655072.

The previous prime is 21300441959. The next prime is 21300442039. The reversal of 21300442021 is 12024400312.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 7693219521 + 13607222500 = 87711^2 + 116650^2 .

It is a cyclic number.

It is not a de Polignac number, because 21300442021 - 2¹¹ = 21300439973 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21300442021.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21300442091) 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, 145893366 + ... + 145893511.

It is an arithmetic number, because the mean of its divisors is an integer number (5398057243).

Almost surely, 2^21300442021 is an apocalyptic number.

It is an amenable number.

21300442021 is a deficient number, since it is larger than the sum of its proper divisors (291786951).

21300442021 is an equidigital number, since it uses as much as digits as its factorization.

21300442021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 291786950.

The product of its (nonzero) digits is 384, while the sum is 19.

Adding to 21300442021 its reverse (12024400312), we get a palindrome (33324842333).

It can be divided in two parts, 213004 and 42021, that added together give a square (255025 = 505²).

The spelling of 21300442021 in words is "twenty-one billion, three hundred million, four hundred forty-two thousand, twenty-one".