21043143203021 has 4 divisors (see below), whose sum is σ = 21399806647200. Its totient is φ = 20686479758844.

The previous prime is 21043143203011. The next prime is 21043143203051. The reversal of 21043143203021 is 12030234134012.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21043143203021 - 2⁴² = 16645096691917 is a prime.

It is a super-2 number, since 2×21043143203021² (a number of 27 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 (21043143203011) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 178331722001 + ... + 178331722118.

It is an arithmetic number, because the mean of its divisors is an integer number (5349951661800).

Almost surely, 2^{21043143203021} is an apocalyptic number.

It is an amenable number.

21043143203021 is a deficient number, since it is larger than the sum of its proper divisors (356663444179).

21043143203021 is an equidigital number, since it uses as much as digits as its factorization.

21043143203021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 356663444178.

The product of its (nonzero) digits is 3456, while the sum is 26.

Adding to 21043143203021 its reverse (12030234134012), we get a palindrome (33073377337033).

The spelling of 21043143203021 in words is "twenty-one trillion, forty-three billion, one hundred forty-three million, two hundred three thousand, twenty-one".