6511738561 has 4 divisors (see below), whose sum is σ = 6736281300. Its totient is φ = 6287195824.

The previous prime is 6511738553. The next prime is 6511738567. The reversal of 6511738561 is 1658371156.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 1436031025 + 5075707536 = 37895^2 + 71244^2 .

It is not a de Polignac number, because 6511738561 - 2³ = 6511738553 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (6511738567) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 112271326 + ... + 112271383.

It is an arithmetic number, because the mean of its divisors is an integer number (1684070325).

Almost surely, 2^6511738561 is an apocalyptic number.

It is an amenable number.

6511738561 is a deficient number, since it is larger than the sum of its proper divisors (224542739).

6511738561 is a wasteful number, since it uses less digits than its factorization.

6511738561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 224542738.

The product of its digits is 151200, while the sum is 43.

The square root of 6511738561 is about 80695.3441098060. The cubic root of 6511738561 is about 1867.3783466419.

The spelling of 6511738561 in words is "six billion, five hundred eleven million, seven hundred thirty-eight thousand, five hundred sixty-one".