2561120123 has 4 divisors (see below), whose sum is σ = 2649434640. Its totient is φ = 2472805608.

The previous prime is 2561120077. The next prime is 2561120141. The reversal of 2561120123 is 3210211652.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 2561120123 - 2¹⁴ = 2561103739 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (2561120623) 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, 44157215 + ... + 44157272.

It is an arithmetic number, because the mean of its divisors is an integer number (662358660).

Almost surely, 2^2561120123 is an apocalyptic number.

2561120123 is a deficient number, since it is larger than the sum of its proper divisors (88314517).

2561120123 is an equidigital number, since it uses as much as digits as its factorization.

2561120123 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 88314516.

The product of its (nonzero) digits is 720, while the sum is 23.

The square root of 2561120123 is about 50607.5105394446. The cubic root of 2561120123 is about 1368.1802473515.

Adding to 2561120123 its reverse (3210211652), we get a palindrome (5771331775).

The spelling of 2561120123 in words is "two billion, five hundred sixty-one million, one hundred twenty thousand, one hundred twenty-three".