51506513 has 4 divisors (see below), whose sum is σ = 52478388. Its totient is φ = 50534640.

The previous prime is 51506503. The next prime is 51506569. The reversal of 51506513 is 31560515.

51506513 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.

It can be written as a sum of positive squares in 2 ways, for example, as 18593344 + 32913169 = 4312^2 + 5737^2 .

It is a cyclic number.

It is not a de Polignac number, because 51506513 - 2²⁰ = 50457937 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (51506503) 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 3 ways as a sum of consecutive naturals, for example, 485858 + ... + 485963.

It is an arithmetic number, because the mean of its divisors is an integer number (13119597).

Almost surely, 2^51506513 is an apocalyptic number.

51506513 is a gapful number since it is divisible by the number (53) formed by its first and last digit.

It is an amenable number.

51506513 is a deficient number, since it is larger than the sum of its proper divisors (971875).

51506513 is an equidigital number, since it uses as much as digits as its factorization.

51506513 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 971874.

The product of its (nonzero) digits is 2250, while the sum is 26.

The square root of 51506513 is about 7176.8038150698. The cubic root of 51506513 is about 372.0666263097.

The spelling of 51506513 in words is "fifty-one million, five hundred six thousand, five hundred thirteen".