21021142321 has 4 divisors (see below), whose sum is σ = 21104892144. Its totient is φ = 20937392500.

The previous prime is 21021142283. The next prime is 21021142327. The reversal of 21021142321 is 12324112012.

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 21021142321 - 2⁷ = 21021142193 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21021142327) 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, 41874535 + ... + 41875036.

It is an arithmetic number, because the mean of its divisors is an integer number (5276223036).

Almost surely, 2^21021142321 is an apocalyptic number.

It is an amenable number.

21021142321 is a deficient number, since it is larger than the sum of its proper divisors (83749823).

21021142321 is an equidigital number, since it uses as much as digits as its factorization.

21021142321 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 83749822.

The product of its (nonzero) digits is 192, while the sum is 19.

Adding to 21021142321 its reverse (12324112012), we get a palindrome (33345254333).

The spelling of 21021142321 in words is "twenty-one billion, twenty-one million, one hundred forty-two thousand, three hundred twenty-one".