6421540 has 12 divisors (see below), whose sum is σ = 13485276. Its totient is φ = 2568608.

The previous prime is 6421523. The next prime is 6421559. The reversal of 6421540 is 451246.

6421540 is digitally balanced in base 5, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 2 ways, for example, as 3912484 + 2509056 = 1978^2 + 1584^2 .

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 160519 + ... + 160558.

It is an arithmetic number, because the mean of its divisors is an integer number (1123773).

Almost surely, 2^6421540 is an apocalyptic number.

It is an amenable number.

6421540 is an abundant number, since it is smaller than the sum of its proper divisors (7063736).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

6421540 is a wasteful number, since it uses less digits than its factorization.

6421540 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 321086 (or 321084 counting only the distinct ones).

The product of its (nonzero) digits is 960, while the sum is 22.

The square root of 6421540 is about 2534.0757684016. The cubic root of 6421540 is about 185.8716114026.

Adding to 6421540 its reverse (451246), we get a palindrome (6872786).

The spelling of 6421540 in words is "six million, four hundred twenty-one thousand, five hundred forty".