6561240 has 128 divisors (see below), whose sum is σ = 23016960. Its totient is φ = 1465344.

The previous prime is 6561223. The next prime is 6561259. The reversal of 6561240 is 421656.

It is a Harshad number since it is a multiple of its sum of digits (24).

It is a self number, because there is not a number n which added to its sum of digits gives 6561240.

It is a congruent number.

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 31 ways as a sum of consecutive naturals, for example, 61267 + ... + 61373.

It is an arithmetic number, because the mean of its divisors is an integer number (179820).

Almost surely, 2^6561240 is an apocalyptic number.

6561240 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 6561240, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (11508480).

6561240 is an abundant number, since it is smaller than the sum of its proper divisors (16455720).

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

6561240 is a wasteful number, since it uses less digits than its factorization.

6561240 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 201 (or 197 counting only the distinct ones).

The product of its (nonzero) digits is 1440, while the sum is 24.

The square root of 6561240 is about 2561.4917528659. The cubic root of 6561240 is about 187.2098267177.

Adding to 6561240 its reverse (421656), we get a palindrome (6982896).

The spelling of 6561240 in words is "six million, five hundred sixty-one thousand, two hundred forty".