51813985 has 4 divisors (see below), whose sum is σ = 62176788. Its totient is φ = 41451184.

The previous prime is 51813961. The next prime is 51813997. The reversal of 51813985 is 58931815.

51813985 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 58931815 = 5 ⋅11786363.

It can be written as a sum of positive squares in 2 ways, for example, as 34433424 + 17380561 = 5868^2 + 4169^2 .

It is a cyclic number.

It is not a de Polignac number, because 51813985 - 2⁷ = 51813857 is a prime.

It is a super-3 number, since 3×51813985³ (a number of 24 digits) contains 333 as substring.

It is a Smith number, since the sum of its digits (40) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

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 3 ways as a sum of consecutive naturals, for example, 5181394 + ... + 5181403.

It is an arithmetic number, because the mean of its divisors is an integer number (15544197).

Almost surely, 2^51813985 is an apocalyptic number.

It is an amenable number.

51813985 is a deficient number, since it is larger than the sum of its proper divisors (10362803).

51813985 is a wasteful number, since it uses less digits than its factorization.

51813985 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10362802.

The product of its digits is 43200, while the sum is 40.

The square root of 51813985 is about 7198.1931760686. The cubic root of 51813985 is about 372.8055178601.

The spelling of 51813985 in words is "fifty-one million, eight hundred thirteen thousand, nine hundred eighty-five".