51706809 has 144 divisors (see below), whose sum is σ = 109166400. Its totient is φ = 23950080.

The previous prime is 51706807. The next prime is 51706859. The reversal of 51706809 is 90860715.

It is not a de Polignac number, because 51706809 - 2¹ = 51706807 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (51706801) by changing a digit.

It is a polite number, since it can be written in 143 ways as a sum of consecutive naturals, for example, 2721402 + ... + 2721420.

It is an arithmetic number, because the mean of its divisors is an integer number (758100).

Almost surely, 2^51706809 is an apocalyptic number.

It is an amenable number.

51706809 is an abundant number, since it is smaller than the sum of its proper divisors (57459591).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

51706809 is a wasteful number, since it uses less digits than its factorization.

51706809 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 81 (or 57 counting only the distinct ones).

The product of its (nonzero) digits is 15120, while the sum is 36.

The square root of 51706809 is about 7190.7446763183. The cubic root of 51706809 is about 372.5482939652.

The spelling of 51706809 in words is "fifty-one million, seven hundred six thousand, eight hundred nine".