6391540 has 12 divisors (see below), whose sum is σ = 13422276. Its totient is φ = 2556608.

The previous prime is 6391537. The next prime is 6391547. The reversal of 6391540 is 451936.

It can be written as a sum of positive squares in 2 ways, for example, as 3370896 + 3020644 = 1836^2 + 1738^2 .

It is an Ulam number.

It is a junction number, because it is equal to n+sod(n) for n = 6391499 and 6391508.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6391547) by changing a digit.

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, 159769 + ... + 159808.

It is an arithmetic number, because the mean of its divisors is an integer number (1118523).

Almost surely, 2^6391540 is an apocalyptic number.

It is an amenable number.

6391540 is an abundant number, since it is smaller than the sum of its proper divisors (7030736).

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

6391540 is a wasteful number, since it uses less digits than its factorization.

6391540 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 319586 (or 319584 counting only the distinct ones).

The product of its (nonzero) digits is 3240, while the sum is 28.

The square root of 6391540 is about 2528.1495208947. The cubic root of 6391540 is about 185.5817092682.

The spelling of 6391540 in words is "six million, three hundred ninety-one thousand, five hundred forty".