2578121729 has 2 divisors, whose sum is σ = 2578121730. Its totient is φ = 2578121728.

The previous prime is 2578121699. The next prime is 2578121731. The reversal of 2578121729 is 9271218752.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 2575765504 + 2356225 = 50752^2 + 1535^2 .

It is a cyclic number.

It is not a de Polignac number, because 2578121729 - 2²⁰ = 2577073153 is a prime.

It is a Sophie Germain prime.

Together with 2578121731, it forms a pair of twin primes.

It is a Chen prime.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 2578121729.

It is not a weakly prime, because it can be changed into another prime (2578121929) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1289060864 + 1289060865.

It is an arithmetic number, because the mean of its divisors is an integer number (1289060865).

Almost surely, 2^2578121729 is an apocalyptic number.

It is an amenable number.

2578121729 is a deficient number, since it is larger than the sum of its proper divisors (1).

2578121729 is an equidigital number, since it uses as much as digits as its factorization.

2578121729 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 141120, while the sum is 44.

The square root of 2578121729 is about 50775.2078183832. The cubic root of 2578121729 is about 1371.2010582032.

The spelling of 2578121729 in words is "two billion, five hundred seventy-eight million, one hundred twenty-one thousand, seven hundred twenty-nine".