51506565 has 16 divisors (see below), whose sum is σ = 89902656. Its totient is φ = 24972800.

The previous prime is 51506503. The next prime is 51506569. The reversal of 51506565 is 56560515.

51506565 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 51506565 - 2⁷ = 51506437 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (33).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51506569) 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, 155916 + ... + 156245.

It is an arithmetic number, because the mean of its divisors is an integer number (5618916).

Almost surely, 2^51506565 is an apocalyptic number.

51506565 is a gapful number since it is divisible by the number (55) formed by its first and last digit.

It is an amenable number.

51506565 is a deficient number, since it is larger than the sum of its proper divisors (38396091).

51506565 is a wasteful number, since it uses less digits than its factorization.

51506565 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 312180.

The product of its (nonzero) digits is 22500, while the sum is 33.

The square root of 51506565 is about 7176.8074378515. The cubic root of 51506565 is about 372.0667515201.

The spelling of 51506565 in words is "fifty-one million, five hundred six thousand, five hundred sixty-five".