6421105421 has 2 divisors, whose sum is σ = 6421105422. Its totient is φ = 6421105420.

The previous prime is 6421105409. The next prime is 6421105531. The reversal of 6421105421 is 1245011246.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 6330589225 + 90516196 = 79565^2 + 9514^2 .

It is a cyclic number.

It is not a de Polignac number, because 6421105421 - 2⁶ = 6421105357 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (6421105021) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3210552710 + 3210552711.

It is an arithmetic number, because the mean of its divisors is an integer number (3210552711).

Almost surely, 2^6421105421 is an apocalyptic number.

It is an amenable number.

6421105421 is a deficient number, since it is larger than the sum of its proper divisors (1).

6421105421 is an equidigital number, since it uses as much as digits as its factorization.

6421105421 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1920, while the sum is 26.

The square root of 6421105421 is about 80131.8003104885. The cubic root of 6421105421 is about 1858.6741834186.

Adding to 6421105421 its reverse (1245011246), we get a palindrome (7666116667).

The spelling of 6421105421 in words is "six billion, four hundred twenty-one million, one hundred five thousand, four hundred twenty-one".