561716581 has 4 divisors (see below), whose sum is σ = 561775564. Its totient is φ = 561657600.

The previous prime is 561716579. The next prime is 561716587. The reversal of 561716581 is 185617165.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 185617165 = 5 ⋅37123433.

It can be written as a sum of positive squares in 2 ways, for example, as 111640356 + 450076225 = 10566^2 + 21215^2 .

It is a cyclic number.

It is not a de Polignac number, because 561716581 - 2¹ = 561716579 is a prime.

It is a super-2 number, since 2×561716581² = 631051034740659122, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (561716587) 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, 11580 + ... + 35461.

It is an arithmetic number, because the mean of its divisors is an integer number (140443891).

Almost surely, 2^561716581 is an apocalyptic number.

It is an amenable number.

561716581 is a deficient number, since it is larger than the sum of its proper divisors (58983).

561716581 is a wasteful number, since it uses less digits than its factorization.

561716581 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 58982.

The product of its digits is 50400, while the sum is 40.

The square root of 561716581 is about 23700.5607739564. The cubic root of 561716581 is about 825.0984056477.

The spelling of 561716581 in words is "five hundred sixty-one million, seven hundred sixteen thousand, five hundred eighty-one".