21140443021 has 2 divisors, whose sum is σ = 21140443022. Its totient is φ = 21140443020.

The previous prime is 21140442991. The next prime is 21140443057. The reversal of 21140443021 is 12034404112.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 14678534025 + 6461908996 = 121155^2 + 80386^2 .

It is a cyclic number.

It is not a de Polignac number, because 21140443021 - 2⁵ = 21140442989 is a prime.

It is a super-2 number, since 2×21140443021² (a number of 21 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21140442983 and 21140443001.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21140443061) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10570221510 + 10570221511.

It is an arithmetic number, because the mean of its divisors is an integer number (10570221511).

Almost surely, 2^21140443021 is an apocalyptic number.

It is an amenable number.

21140443021 is a deficient number, since it is larger than the sum of its proper divisors (1).

21140443021 is an equidigital number, since it uses as much as digits as its factorization.

21140443021 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 768, while the sum is 22.

Adding to 21140443021 its reverse (12034404112), we get a palindrome (33174847133).

The spelling of 21140443021 in words is "twenty-one billion, one hundred forty million, four hundred forty-three thousand, twenty-one".