6561761565265 has 4 divisors (see below), whose sum is σ = 7874113878324. Its totient is φ = 5249409252208.

The previous prime is 6561761565239. The next prime is 6561761565299. The reversal of 6561761565265 is 5625651671656.

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 1277390467089 + 5284371098176 = 1130217^2 + 2298776^2 .

It is a cyclic number.

It is not a de Polignac number, because 6561761565265 - 2²¹ = 6561759468113 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 656176156522 + ... + 656176156531.

It is an arithmetic number, because the mean of its divisors is an integer number (1968528469581).

Almost surely, 2^{6561761565265} is an apocalyptic number.

It is an amenable number.

6561761565265 is a deficient number, since it is larger than the sum of its proper divisors (1312352313059).

6561761565265 is a wasteful number, since it uses less digits than its factorization.

6561761565265 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1312352313058.

The product of its digits is 68040000, while the sum is 61.

The spelling of 6561761565265 in words is "six trillion, five hundred sixty-one billion, seven hundred sixty-one million, five hundred sixty-five thousand, two hundred sixty-five".