51549542809181 has 4 divisors (see below), whose sum is σ = 51555773875452. Its totient is φ = 51543311742912.

The previous prime is 51549542809169. The next prime is 51549542809249. The reversal of 51549542809181 is 18190824594515.

It is a happy number.

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 43856963206681 + 7692579602500 = 6622459^2 + 2773550^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-51549542809181 is a prime.

It is a super-2 number, since 2×51549542809181² (a number of 28 digits) contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51549542800181) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3115520726 + ... + 3115537271.

It is an arithmetic number, because the mean of its divisors is an integer number (12888943468863).

Almost surely, 2^{51549542809181} is an apocalyptic number.

It is an amenable number.

51549542809181 is a deficient number, since it is larger than the sum of its proper divisors (6231066271).

51549542809181 is an equidigital number, since it uses as much as digits as its factorization.

51549542809181 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6231066270.

The product of its (nonzero) digits is 20736000, while the sum is 62.

The spelling of 51549542809181 in words is "fifty-one trillion, five hundred forty-nine billion, five hundred forty-two million, eight hundred nine thousand, one hundred eighty-one".