21421331421 has 24 divisors (see below), whose sum is σ = 34296701184. Its totient is φ = 11845895040.

The previous prime is 21421331417. The next prime is 21421331441. The reversal of 21421331421 is 12413312412.

It is not a de Polignac number, because 21421331421 - 2² = 21421331417 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21421331391 and 21421331400.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21421331441) 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 23 ways as a sum of consecutive naturals, for example, 2345820 + ... + 2354933.

It is an arithmetic number, because the mean of its divisors is an integer number (1429029216).

Almost surely, 2^21421331421 is an apocalyptic number.

21421331421 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

21421331421 is a deficient number, since it is larger than the sum of its proper divisors (12875369763).

21421331421 is a wasteful number, since it uses less digits than its factorization.

21421331421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4700801 (or 4700794 counting only the distinct ones).

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

Adding to 21421331421 its reverse (12413312412), we get a palindrome (33834643833).

The spelling of 21421331421 in words is "twenty-one billion, four hundred twenty-one million, three hundred thirty-one thousand, four hundred twenty-one".