51168809 has 2 divisors, whose sum is σ = 51168810. Its totient is φ = 51168808.

The previous prime is 51168781. The next prime is 51168811. The reversal of 51168809 is 90886115.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 50013184 + 1155625 = 7072^2 + 1075^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-51168809 is a prime.

Together with 51168811, it forms a pair of twin primes.

It is a Chen prime.

It is equal to p_3066959 and since 51168809 and 3066959 have the same sum of digits, it is a Honaker prime.

It is not a weakly prime, because it can be changed into another prime (51168889) 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, 25584404 + 25584405.

It is an arithmetic number, because the mean of its divisors is an integer number (25584405).

Almost surely, 2^51168809 is an apocalyptic number.

It is an amenable number.

51168809 is a deficient number, since it is larger than the sum of its proper divisors (1).

51168809 is an equidigital number, since it uses as much as digits as its factorization.

51168809 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 17280, while the sum is 38.

The square root of 51168809 is about 7153.2376585711. The cubic root of 51168809 is about 371.2516873107.

The spelling of 51168809 in words is "fifty-one million, one hundred sixty-eight thousand, eight hundred nine".