2581217563 has 4 divisors (see below), whose sum is σ = 2581328088. Its totient is φ = 2581107040.

The previous prime is 2581217531. The next prime is 2581217591. The reversal of 2581217563 is 3657121852.

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.

It is a cyclic number.

It is not a de Polignac number, because 2581217563 - 2⁵ = 2581217531 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (2581217363) 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, 4981 + ... + 72022.

It is an arithmetic number, because the mean of its divisors is an integer number (645332022).

Almost surely, 2^2581217563 is an apocalyptic number.

2581217563 is a deficient number, since it is larger than the sum of its proper divisors (110525).

2581217563 is an equidigital number, since it uses as much as digits as its factorization.

2581217563 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 110524.

The product of its digits is 100800, while the sum is 40.

The square root of 2581217563 is about 50805.6843571662. The cubic root of 2581217563 is about 1371.7496892461.

The spelling of 2581217563 in words is "two billion, five hundred eighty-one million, two hundred seventeen thousand, five hundred sixty-three".