2256611021 has 4 divisors (see below), whose sum is σ = 2578984032. Its totient is φ = 1934238012.

The previous prime is 2256611009. The next prime is 2256611023. The reversal of 2256611021 is 1201166522.

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: 1201166522 = 2 ⋅600583261.

It is not a de Polignac number, because 2256611021 - 2¹⁰ = 2256609997 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2256611023) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 161186495 + ... + 161186508.

It is an arithmetic number, because the mean of its divisors is an integer number (644746008).

Almost surely, 2^2256611021 is an apocalyptic number.

It is an amenable number.

2256611021 is a deficient number, since it is larger than the sum of its proper divisors (322373011).

2256611021 is an equidigital number, since it uses as much as digits as its factorization.

2256611021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 322373010.

The product of its (nonzero) digits is 1440, while the sum is 26.

The square root of 2256611021 is about 47503.8000690471. The cubic root of 2256611021 is about 1311.6528330297.

Adding to 2256611021 its reverse (1201166522), we get a palindrome (3457777543).

The spelling of 2256611021 in words is "two billion, two hundred fifty-six million, six hundred eleven thousand, twenty-one".