51139709 has 2 divisors, whose sum is σ = 51139710. Its totient is φ = 51139708.

The previous prime is 51139681. The next prime is 51139717. The reversal of 51139709 is 90793115.

51139709 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 31114084 + 20025625 = 5578^2 + 4475^2 .

It is a cyclic number.

It is not a de Polignac number, because 51139709 - 2¹⁶ = 51074173 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (51139609) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 25569854 + 25569855.

It is an arithmetic number, because the mean of its divisors is an integer number (25569855).

Almost surely, 2^51139709 is an apocalyptic number.

It is an amenable number.

51139709 is a deficient number, since it is larger than the sum of its proper divisors (1).

51139709 is an equidigital number, since it uses as much as digits as its factorization.

51139709 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 8505, while the sum is 35.

The square root of 51139709 is about 7151.2033253153. The cubic root of 51139709 is about 371.1812962988.

The spelling of 51139709 in words is "fifty-one million, one hundred thirty-nine thousand, seven hundred nine".