51135965891 has 2 divisors, whose sum is σ = 51135965892. Its totient is φ = 51135965890.

The previous prime is 51135965819. The next prime is 51135965893. The reversal of 51135965891 is 19856953115.

Together with previous prime (51135965819) it forms an Ormiston pair, because they use the same digits, order apart.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-51135965891 is a prime.

It is a super-2 number, since 2×51135965891² (a number of 22 digits) contains 22 as substring.

Together with 51135965893, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (51135965893) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 25567982945 + 25567982946.

It is an arithmetic number, because the mean of its divisors is an integer number (25567982946).

Almost surely, 2^51135965891 is an apocalyptic number.

51135965891 is a deficient number, since it is larger than the sum of its proper divisors (1).

51135965891 is an equidigital number, since it uses as much as digits as its factorization.

51135965891 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1458000, while the sum is 53.

The spelling of 51135965891 in words is "fifty-one billion, one hundred thirty-five million, nine hundred sixty-five thousand, eight hundred ninety-one".