51305665 has 16 divisors (see below), whose sum is σ = 63904896. Its totient is φ = 39513600.

The previous prime is 51305647. The next prime is 51305671. The reversal of 51305665 is 56650315.

51305665 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 51305665 - 2¹⁷ = 51174593 is a prime.

It is a super-2 number, since 2×51305665² = 5264542522184450, which contains 22 as substring.

It is a Duffinian number.

It is an unprimeable number.

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 in 15 ways as a sum of consecutive naturals, for example, 13585 + ... + 16945.

It is an arithmetic number, because the mean of its divisors is an integer number (3994056).

Almost surely, 2^51305665 is an apocalyptic number.

It is an amenable number.

51305665 is a deficient number, since it is larger than the sum of its proper divisors (12599231).

51305665 is a wasteful number, since it uses less digits than its factorization.

51305665 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3480.

The product of its (nonzero) digits is 13500, while the sum is 31.

The square root of 51305665 is about 7162.7972887692. The cubic root of 51305665 is about 371.5823756870.

The spelling of 51305665 in words is "fifty-one million, three hundred five thousand, six hundred sixty-five".