51918938497 has 4 divisors (see below), whose sum is σ = 51920901076. Its totient is φ = 51916975920.

The previous prime is 51918938459. The next prime is 51918938503. The reversal of 51918938497 is 79483981915.

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 36525325456 + 15393613041 = 191116^2 + 124071^2 .

It is a cyclic number.

It is not a de Polignac number, because 51918938497 - 2²⁷ = 51784720769 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (51918938437) 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, 941058 + ... + 994699.

It is an arithmetic number, because the mean of its divisors is an integer number (12980225269).

Almost surely, 2^51918938497 is an apocalyptic number.

It is an amenable number.

51918938497 is a deficient number, since it is larger than the sum of its proper divisors (1962579).

51918938497 is a wasteful number, since it uses less digits than its factorization.

51918938497 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1962578.

The product of its digits is 19595520, while the sum is 64.

The spelling of 51918938497 in words is "fifty-one billion, nine hundred eighteen million, nine hundred thirty-eight thousand, four hundred ninety-seven".