21421431321 has 4 divisors (see below), whose sum is σ = 28561908432. Its totient is φ = 14280954212.

The previous prime is 21421431319. The next prime is 21421431331. The reversal of 21421431321 is 12313412412.

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 21421431321 - 2¹ = 21421431319 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21421431291 and 21421431300.

It is not an unprimeable number, because it can be changed into a prime (21421431331) 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 in 3 ways as a sum of consecutive naturals, for example, 3570238551 + ... + 3570238556.

It is an arithmetic number, because the mean of its divisors is an integer number (7140477108).

Almost surely, 2^21421431321 is an apocalyptic number.

It is an amenable number.

21421431321 is a deficient number, since it is larger than the sum of its proper divisors (7140477111).

21421431321 is an equidigital number, since it uses as much as digits as its factorization.

21421431321 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7140477110.

The product of its digits is 1152, while the sum is 24.

Adding to 21421431321 its reverse (12313412412), we get a palindrome (33734843733).

The spelling of 21421431321 in words is "twenty-one billion, four hundred twenty-one million, four hundred thirty-one thousand, three hundred twenty-one".