6540561 has 8 divisors (see below), whose sum is σ = 9689760. Its totient is φ = 4360356.

The previous prime is 6540557. The next prime is 6540587. The reversal of 6540561 is 1650456.

It is a happy number.

6540561 is a `hidden beast` number, since 65 + 40 + 561 = 666.

It is not a de Polignac number, because 6540561 - 2² = 6540557 is a prime.

It is a super-3 number, since 3×6540561³ (a number of 21 digits) contains 333 as substring.

It is a Harshad number since it is a multiple of its sum of digits (27), and also a Moran number because the ratio is a prime number: 242243 = 6540561 / (6 + 5 + 4 + 0 + 5 + 6 + 1).

It is not an unprimeable number, because it can be changed into a prime (6540511) 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 7 ways as a sum of consecutive naturals, for example, 121095 + ... + 121148.

It is an arithmetic number, because the mean of its divisors is an integer number (1211220).

Almost surely, 2^6540561 is an apocalyptic number.

It is an amenable number.

6540561 is a deficient number, since it is larger than the sum of its proper divisors (3149199).

6540561 is a wasteful number, since it uses less digits than its factorization.

6540561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 242252 (or 242246 counting only the distinct ones).

The product of its (nonzero) digits is 3600, while the sum is 27.

The square root of 6540561 is about 2557.4520523365. The cubic root of 6540561 is about 187.0129439027.

The spelling of 6540561 in words is "six million, five hundred forty thousand, five hundred sixty-one".