51085378891 has 8 divisors (see below), whose sum is σ = 52401077568. Its totient is φ = 49773000000.

The previous prime is 51085378873. The next prime is 51085378921. The reversal of 51085378891 is 19887358015.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 51085378891 - 2⁵ = 51085378859 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (51085378871) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 798760 + ... + 860341.

It is an arithmetic number, because the mean of its divisors is an integer number (6550134696).

Almost surely, 2^51085378891 is an apocalyptic number.

51085378891 is a deficient number, since it is larger than the sum of its proper divisors (1315698677).

51085378891 is a wasteful number, since it uses less digits than its factorization.

51085378891 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1659893.

The product of its (nonzero) digits is 2419200, while the sum is 55.

The spelling of 51085378891 in words is "fifty-one billion, eighty-five million, three hundred seventy-eight thousand, eight hundred ninety-one".