6561165605 has 4 divisors (see below), whose sum is σ = 7873398732. Its totient is φ = 5248932480.

The previous prime is 6561165601. The next prime is 6561165641. The reversal of 6561165605 is 5065611656.

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 4509256801 + 2051908804 = 67151^2 + 45298^2 .

It is not a de Polignac number, because 6561165605 - 2² = 6561165601 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6561165601) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 656116556 + ... + 656116565.

It is an arithmetic number, because the mean of its divisors is an integer number (1968349683).

Almost surely, 2^6561165605 is an apocalyptic number.

It is an amenable number.

6561165605 is a deficient number, since it is larger than the sum of its proper divisors (1312233127).

6561165605 is a wasteful number, since it uses less digits than its factorization.

6561165605 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1312233126.

The product of its (nonzero) digits is 162000, while the sum is 41.

The square root of 6561165605 is about 81001.0222466359. The cubic root of 6561165605 is about 1872.0911915187.

The spelling of 6561165605 in words is "six billion, five hundred sixty-one million, one hundred sixty-five thousand, six hundred five".