2256556521 has 4 divisors (see below), whose sum is σ = 3008742032. Its totient is φ = 1504371012.

The previous prime is 2256556513. The next prime is 2256556543. The reversal of 2256556521 is 1256556522.

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 2256556521 - 2³ = 2256556513 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 2256556521.

It is not an unprimeable number, because it can be changed into a prime (2256556571) 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, 376092751 + ... + 376092756.

It is an arithmetic number, because the mean of its divisors is an integer number (752185508).

Almost surely, 2^2256556521 is an apocalyptic number.

It is an amenable number.

2256556521 is a deficient number, since it is larger than the sum of its proper divisors (752185511).

2256556521 is an equidigital number, since it uses as much as digits as its factorization.

2256556521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 752185510.

The product of its digits is 180000, while the sum is 39.

The square root of 2256556521 is about 47503.2264272649. The cubic root of 2256556521 is about 1311.6422735884.

Subtracting from 2256556521 its reverse (1256556522), we obtain a palindrome (999999999).

The spelling of 2256556521 in words is "two billion, two hundred fifty-six million, five hundred fifty-six thousand, five hundred twenty-one".