6540645561 has 8 divisors (see below), whose sum is σ = 8741003040. Its totient is φ = 4350359232.

The previous prime is 6540645523. The next prime is 6540645589. The reversal of 6540645561 is 1655460456.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 6540645561 - 2⁶ = 6540645497 is a prime.

It is not an unprimeable number, because it can be changed into a prime (6540645521) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2516271 + ... + 2518868.

It is an arithmetic number, because the mean of its divisors is an integer number (1092625380).

Almost surely, 2^6540645561 is an apocalyptic number.

It is an amenable number.

6540645561 is a deficient number, since it is larger than the sum of its proper divisors (2200357479).

6540645561 is a wasteful number, since it uses less digits than its factorization.

6540645561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5035575.

The product of its (nonzero) digits is 432000, while the sum is 42.

The square root of 6540645561 is about 80874.2577152953. The cubic root of 6540645561 is about 1870.1374984449.

The spelling of 6540645561 in words is "six billion, five hundred forty million, six hundred forty-five thousand, five hundred sixty-one".