51688809 has 6 divisors (see below), whose sum is σ = 74661626. Its totient is φ = 34459200.

The previous prime is 51688807. The next prime is 51688829. The reversal of 51688809 is 90888615.

51688809 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in only one way, i.e., 48608784 + 3080025 = 6972^2 + 1755^2 .

It is not a de Polignac number, because 51688809 - 2¹ = 51688807 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (51688807) 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 in 5 ways as a sum of consecutive naturals, for example, 2871592 + ... + 2871609.

Almost surely, 2^51688809 is an apocalyptic number.

It is an amenable number.

51688809 is a deficient number, since it is larger than the sum of its proper divisors (22972817).

51688809 is a wasteful number, since it uses less digits than its factorization.

51688809 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5743207 (or 5743204 counting only the distinct ones).

The product of its (nonzero) digits is 138240, while the sum is 45.

The square root of 51688809 is about 7189.4929584777. The cubic root of 51688809 is about 372.5050588626.

The spelling of 51688809 in words is "fifty-one million, six hundred eighty-eight thousand, eight hundred nine".