51863444681 has 4 divisors (see below), whose sum is σ = 52322413332. Its totient is φ = 51404476032.

The previous prime is 51863444669. The next prime is 51863444687. The reversal of 51863444681 is 18644436815.

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 7811731456 + 44051713225 = 88384^2 + 209885^2 .

It is a cyclic number.

It is not a de Polignac number, because 51863444681 - 2¹⁴ = 51863428297 is a prime.

It is a super-2 number, since 2×51863444681² (a number of 22 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (51863444687) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 229484156 + ... + 229484381.

It is an arithmetic number, because the mean of its divisors is an integer number (13080603333).

Almost surely, 2^51863444681 is an apocalyptic number.

It is an amenable number.

51863444681 is a deficient number, since it is larger than the sum of its proper divisors (458968651).

51863444681 is a wasteful number, since it uses less digits than its factorization.

51863444681 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 458968650.

The product of its digits is 2211840, while the sum is 50.

The spelling of 51863444681 in words is "fifty-one billion, eight hundred sixty-three million, four hundred forty-four thousand, six hundred eighty-one".