51081370042781 has 4 divisors (see below), whose sum is σ = 55010706199932. Its totient is φ = 47152033885632.

The previous prime is 51081370042777. The next prime is 51081370042849. The reversal of 51081370042781 is 18724007318015.

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 4556816008900 + 46524554033881 = 2134670^2 + 6820891^2 .

It is not a de Polignac number, because 51081370042781 - 2² = 51081370042777 is a prime.

It is a super-2 number, since 2×51081370042781² (a number of 28 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51081370045781) 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, 1964668078556 + ... + 1964668078581.

It is an arithmetic number, because the mean of its divisors is an integer number (13752676549983).

Almost surely, 2^{51081370042781} is an apocalyptic number.

It is an amenable number.

51081370042781 is a deficient number, since it is larger than the sum of its proper divisors (3929336157151).

51081370042781 is a wasteful number, since it uses less digits than its factorization.

51081370042781 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3929336157150.

The product of its (nonzero) digits is 376320, while the sum is 47.

The spelling of 51081370042781 in words is "fifty-one trillion, eighty-one billion, three hundred seventy million, forty-two thousand, seven hundred eighty-one".