21072422021 has 12 divisors (see below), whose sum is σ = 24545242188. Its totient is φ = 18038184192.

The previous prime is 21072422011. The next prime is 21072422051. The reversal of 21072422021 is 12022427012.

It can be written as a sum of positive squares in 2 ways, for example, as 17596022500 + 3476399521 = 132650^2 + 58961^2 .

It is not a de Polignac number, because 21072422021 - 2¹⁸ = 21072159877 is a prime.

It is a super-2 number, since 2×21072422021² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21072422011) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 246956 + ... + 321141.

It is an arithmetic number, because the mean of its divisors is an integer number (2045436849).

Almost surely, 2^21072422021 is an apocalyptic number.

It is an amenable number.

21072422021 is a deficient number, since it is larger than the sum of its proper divisors (3472820167).

21072422021 is an equidigital number, since it uses as much as digits as its factorization.

21072422021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 568868 (or 568861 counting only the distinct ones).

The product of its (nonzero) digits is 896, while the sum is 23.

Adding to 21072422021 its reverse (12022427012), we get a palindrome (33094849033).

The spelling of 21072422021 in words is "twenty-one billion, seventy-two million, four hundred twenty-two thousand, twenty-one".