51811015181 has 2 divisors, whose sum is σ = 51811015182. Its totient is φ = 51811015180.

The previous prime is 51811015163. The next prime is 51811015183. The reversal of 51811015181 is 18151011815.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 40888884100 + 10922131081 = 202210^2 + 104509^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-51811015181 is a prime.

It is a super-2 number, since 2×51811015181² (a number of 22 digits) contains 22 as substring.

It is a Sophie Germain prime.

Together with 51811015183, it forms a pair of twin primes.

It is a Chen prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (51811015183) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 25905507590 + 25905507591.

It is an arithmetic number, because the mean of its divisors is an integer number (25905507591).

Almost surely, 2^51811015181 is an apocalyptic number.

It is an amenable number.

51811015181 is a deficient number, since it is larger than the sum of its proper divisors (1).

51811015181 is an equidigital number, since it uses as much as digits as its factorization.

51811015181 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1600, while the sum is 32.

Adding to 51811015181 its reverse (18151011815), we get a palindrome (69962026996).

The spelling of 51811015181 in words is "fifty-one billion, eight hundred eleven million, fifteen thousand, one hundred eighty-one".