51242111513 has 4 divisors (see below), whose sum is σ = 51242756388. Its totient is φ = 51241466640.

The previous prime is 51242111341. The next prime is 51242111533. The reversal of 51242111513 is 31511124215.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 31511124215 = 5 ⋅6302224843.

It can be written as a sum of positive squares in 2 ways, for example, as 45066194944 + 6175916569 = 212288^2 + 78587^2 .

It is a cyclic number.

It is not a de Polignac number, because 51242111513 - 2¹⁰ = 51242110489 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (51242111533) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 183206 + ... + 368847.

It is an arithmetic number, because the mean of its divisors is an integer number (12810689097).

Almost surely, 2^51242111513 is an apocalyptic number.

It is an amenable number.

51242111513 is a deficient number, since it is larger than the sum of its proper divisors (644875).

51242111513 is an equidigital number, since it uses as much as digits as its factorization.

51242111513 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 644874.

The product of its digits is 1200, while the sum is 26.

Adding to 51242111513 its reverse (31511124215), we get a palindrome (82753235728).

The spelling of 51242111513 in words is "fifty-one billion, two hundred forty-two million, one hundred eleven thousand, five hundred thirteen".