51605865 has 12 divisors (see below), whose sum is σ = 89450244. Its totient is φ = 27523104.

The previous prime is 51605833. The next prime is 51605909. The reversal of 51605865 is 56850615.

51605865 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 2 ways, for example, as 20903184 + 30702681 = 4572^2 + 5541^2 .

It is not a de Polignac number, because 51605865 - 2⁵ = 51605833 is a prime.

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 11 ways as a sum of consecutive naturals, for example, 573354 + ... + 573443.

It is an arithmetic number, because the mean of its divisors is an integer number (7454187).

Almost surely, 2^51605865 is an apocalyptic number.

It is an amenable number.

51605865 is a deficient number, since it is larger than the sum of its proper divisors (37844379).

51605865 is a wasteful number, since it uses less digits than its factorization.

51605865 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1146808 (or 1146805 counting only the distinct ones).

The product of its (nonzero) digits is 36000, while the sum is 36.

The square root of 51605865 is about 7183.7222245852. The cubic root of 51605865 is about 372.3057017123.

It can be divided in two parts, 5160 and 5865, that added together give a square (11025 = 105²).

The spelling of 51605865 in words is "fifty-one million, six hundred five thousand, eight hundred sixty-five".