2656042121 has 4 divisors (see below), whose sum is σ = 2664694032. Its totient is φ = 2647390212.

The previous prime is 2656042097. The next prime is 2656042171. The reversal of 2656042121 is 1212406562.

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: 1212406562 = 2 ⋅606203281.

It is a cyclic number.

It is not a de Polignac number, because 2656042121 - 2¹⁸ = 2655779977 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (2656042171) 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, 4325495 + ... + 4326108.

It is an arithmetic number, because the mean of its divisors is an integer number (666173508).

Almost surely, 2^2656042121 is an apocalyptic number.

It is an amenable number.

2656042121 is a deficient number, since it is larger than the sum of its proper divisors (8651911).

2656042121 is an equidigital number, since it uses as much as digits as its factorization.

2656042121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8651910.

The product of its (nonzero) digits is 5760, while the sum is 29.

The square root of 2656042121 is about 51536.8035582340. The cubic root of 2656042121 is about 1384.8784352894.

Adding to 2656042121 its reverse (1212406562), we get a palindrome (3868448683).

The spelling of 2656042121 in words is "two billion, six hundred fifty-six million, forty-two thousand, one hundred twenty-one".