2561531263 has 4 divisors (see below), whose sum is σ = 2561634720. Its totient is φ = 2561427808.

The previous prime is 2561531257. The next prime is 2561531267. The reversal of 2561531263 is 3621351652.

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 2561531263 - 2²⁵ = 2527976831 is a prime.

It is a super-2 number, since 2×2561531263² = 13122884822652750338, 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 (2561531267) 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, 9831 + ... + 72247.

It is an arithmetic number, because the mean of its divisors is an integer number (640408680).

Almost surely, 2^2561531263 is an apocalyptic number.

2561531263 is a deficient number, since it is larger than the sum of its proper divisors (103457).

2561531263 is an equidigital number, since it uses as much as digits as its factorization.

2561531263 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 103456.

The product of its digits is 32400, while the sum is 34.

The square root of 2561531263 is about 50611.5724217298. The cubic root of 2561531263 is about 1368.2534553624.

The spelling of 2561531263 in words is "two billion, five hundred sixty-one million, five hundred thirty-one thousand, two hundred sixty-three".