8561638641 has 4 divisors (see below), whose sum is σ = 11415518192. Its totient is φ = 5707759092.

The previous prime is 8561638639. The next prime is 8561638649. The reversal of 8561638641 is 1468361658.

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.

It is not a de Polignac number, because 8561638641 - 2¹ = 8561638639 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (8561638649) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1426939771 + ... + 1426939776.

It is an arithmetic number, because the mean of its divisors is an integer number (2853879548).

Almost surely, 2^8561638641 is an apocalyptic number.

It is an amenable number.

8561638641 is a deficient number, since it is larger than the sum of its proper divisors (2853879551).

8561638641 is a wasteful number, since it uses less digits than its factorization.

8561638641 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2853879550.

The product of its digits is 829440, while the sum is 48.

The square root of 8561638641 is about 92529.1232045349. The cubic root of 8561638641 is about 2045.7487661271.

The spelling of 8561638641 in words is "eight billion, five hundred sixty-one million, six hundred thirty-eight thousand, six hundred forty-one".