51218512313 has 4 divisors (see below), whose sum is σ = 52984667940. Its totient is φ = 49452356688.

The previous prime is 51218512277. The next prime is 51218512333. The reversal of 51218512313 is 31321581215.

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 16298862889 + 34919649424 = 127667^2 + 186868^2 .

It is a cyclic number.

It is not a de Polignac number, because 51218512313 - 2⁸ = 51218512057 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 51218512313.

It is not an unprimeable number, because it can be changed into a prime (51218512333) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 883077770 + ... + 883077827.

It is an arithmetic number, because the mean of its divisors is an integer number (13246166985).

Almost surely, 2^51218512313 is an apocalyptic number.

It is an amenable number.

51218512313 is a deficient number, since it is larger than the sum of its proper divisors (1766155627).

51218512313 is a wasteful number, since it uses less digits than its factorization.

51218512313 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1766155626.

The product of its digits is 7200, while the sum is 32.

The spelling of 51218512313 in words is "fifty-one billion, two hundred eighteen million, five hundred twelve thousand, three hundred thirteen".