8111561 has 4 divisors (see below), whose sum is σ = 8391300. Its totient is φ = 7831824.

The previous prime is 8111539. The next prime is 8111573. The reversal of 8111561 is 1651118.

It is a happy number.

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 5953600 + 2157961 = 2440^2 + 1469^2 .

It is a cyclic number.

It is not a de Polignac number, because 8111561 - 2¹⁴ = 8095177 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (8111501) 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, 139826 + ... + 139883.

It is an arithmetic number, because the mean of its divisors is an integer number (2097825).

Almost surely, 2^8111561 is an apocalyptic number.

It is an amenable number.

8111561 is a deficient number, since it is larger than the sum of its proper divisors (279739).

8111561 is a wasteful number, since it uses less digits than its factorization.

8111561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 279738.

The product of its digits is 240, while the sum is 23.

The square root of 8111561 is about 2848.0802306115. The cubic root of 8111561 is about 200.9253866936.

Adding to 8111561 its reverse (1651118), we get a palindrome (9762679).

The spelling of 8111561 in words is "eight million, one hundred eleven thousand, five hundred sixty-one".