51809559 has 16 divisors (see below), whose sum is σ = 70397952. Its totient is φ = 33884928.

The previous prime is 51809533. The next prime is 51809629. The reversal of 51809559 is 95590815.

It is a happy number.

51809559 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 51809559 - 2⁷ = 51809431 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 51809559.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51809519) 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 15 ways as a sum of consecutive naturals, for example, 76647 + ... + 77319.

It is an arithmetic number, because the mean of its divisors is an integer number (4399872).

Almost surely, 2^51809559 is an apocalyptic number.

51809559 is a deficient number, since it is larger than the sum of its proper divisors (18588393).

51809559 is a wasteful number, since it uses less digits than its factorization.

51809559 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1126.

The product of its (nonzero) digits is 81000, while the sum is 42.

The square root of 51809559 is about 7197.8857312408. The cubic root of 51809559 is about 372.7949024236.

The spelling of 51809559 in words is "fifty-one million, eight hundred nine thousand, five hundred fifty-nine".