8109561 has 16 divisors (see below), whose sum is σ = 12052800. Its totient is φ = 4819968.

The previous prime is 8109557. The next prime is 8109581. The reversal of 8109561 is 1659018.

It is a happy number.

It is not a de Polignac number, because 8109561 - 2² = 8109557 is a prime.

It is a super-2 number, since 2×8109561² = 131529959225442, which contains 22 as substring.

It is an Ulam number.

It is not an unprimeable number, because it can be changed into a prime (8109511) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 3216 + ... + 5153.

It is an arithmetic number, because the mean of its divisors is an integer number (753300).

Almost surely, 2^8109561 is an apocalyptic number.

It is an amenable number.

8109561 is a deficient number, since it is larger than the sum of its proper divisors (3943239).

8109561 is a wasteful number, since it uses less digits than its factorization.

8109561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8408.

The product of its (nonzero) digits is 2160, while the sum is 30.

The square root of 8109561 is about 2847.7290952617. The cubic root of 8109561 is about 200.9088718368.

The spelling of 8109561 in words is "eight million, one hundred nine thousand, five hundred sixty-one".