8091641065561 has 27 divisors (see below), whose sum is σ = 8566486940479. Its totient is φ = 7642729204208.

The previous prime is 8091641065559. The next prime is 8091641065589. The reversal of 8091641065561 is 1655601461908.

The square root of 8091641065561 is 2844581.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in only one way, i.e., 4243060297161 + 3848580768400 = 2059869^2 + 1961780^2 .

It is not a de Polignac number, because 8091641065561 - 2¹ = 8091641065559 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 8091641065499 and 8091641065508.

It is not an unprimeable number, because it can be changed into a prime (8091641765561) by changing a digit.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 3877162860 + ... + 3877164946.

Almost surely, 2^{8091641065561} is an apocalyptic number.

8091641065561 is the 2844581-st square number.

8091641065561 is the 1422291-st centered octagonal number.

It is an amenable number.

8091641065561 is a deficient number, since it is larger than the sum of its proper divisors (474845874918).

8091641065561 is an frugal number, since it uses more digits than its factorization.

8091641065561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4326 (or 2163 counting only the distinct ones).

The product of its (nonzero) digits is 1555200, while the sum is 52.

The spelling of 8091641065561 in words is "eight trillion, ninety-one billion, six hundred forty-one million, sixty-five thousand, five hundred sixty-one".