51538511917 has 2 divisors, whose sum is σ = 51538511918. Its totient is φ = 51538511916.

The previous prime is 51538511911. The next prime is 51538511953. The reversal of 51538511917 is 71911583515.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 51233869801 + 304642116 = 226349^2 + 17454^2 .

It is a cyclic number.

It is not a de Polignac number, because 51538511917 - 2⁷ = 51538511789 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (51538511911) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 25769255958 + 25769255959.

It is an arithmetic number, because the mean of its divisors is an integer number (25769255959).

Almost surely, 2^51538511917 is an apocalyptic number.

It is an amenable number.

51538511917 is a deficient number, since it is larger than the sum of its proper divisors (1).

51538511917 is an equidigital number, since it uses as much as digits as its factorization.

51538511917 is an evil number, because the sum of its binary digits is even.

The product of its digits is 189000, while the sum is 46.

The spelling of 51538511917 in words is "fifty-one billion, five hundred thirty-eight million, five hundred eleven thousand, nine hundred seventeen".