51815545 has 4 divisors (see below), whose sum is σ = 62178660. Its totient is φ = 41452432.

The previous prime is 51815509. The next prime is 51815551. The reversal of 51815545 is 54551815.

51815545 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: 54551815 = 5 ⋅10910363.

It can be written as a sum of positive squares in 2 ways, for example, as 29800681 + 22014864 = 5459^2 + 4692^2 .

It is a cyclic number.

It is not a de Polignac number, because 51815545 - 2¹⁹ = 51291257 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 51815545.

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, 5181550 + ... + 5181559.

It is an arithmetic number, because the mean of its divisors is an integer number (15544665).

Almost surely, 2^51815545 is an apocalyptic number.

It is an amenable number.

51815545 is a deficient number, since it is larger than the sum of its proper divisors (10363115).

51815545 is a wasteful number, since it uses less digits than its factorization.

51815545 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10363114.

The product of its digits is 20000, while the sum is 34.

The square root of 51815545 is about 7198.3015357791. The cubic root of 51815545 is about 372.8092592617.

The spelling of 51815545 in words is "fifty-one million, eight hundred fifteen thousand, five hundred forty-five".