8563661 has 4 divisors (see below), whose sum is σ = 9014400. Its totient is φ = 8112924.

The previous prime is 8563637. The next prime is 8563693. The reversal of 8563661 is 1663658.

8563661 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 1663658 = 2 ⋅831829.

It is a de Polignac number, because none of the positive numbers 2^k-8563661 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (8563861) 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, 225341 + ... + 225378.

It is an arithmetic number, because the mean of its divisors is an integer number (2253600).

Almost surely, 2^8563661 is an apocalyptic number.

It is an amenable number.

8563661 is a deficient number, since it is larger than the sum of its proper divisors (450739).

8563661 is a wasteful number, since it uses less digits than its factorization.

8563661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 450738.

The product of its digits is 25920, while the sum is 35.

The square root of 8563661 is about 2926.3733528038. The cubic root of 8563661 is about 204.5909830027.

The spelling of 8563661 in words is "eight million, five hundred sixty-three thousand, six hundred sixty-one".