51138778871 has 4 divisors (see below), whose sum is σ = 54146942352. Its totient is φ = 48130615392.

The previous prime is 51138778853. The next prime is 51138778879. The reversal of 51138778871 is 17887783115.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 51138778871 - 2¹⁸ = 51138516727 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51138778879) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1504081715 + ... + 1504081748.

It is an arithmetic number, because the mean of its divisors is an integer number (13536735588).

Almost surely, 2^51138778871 is an apocalyptic number.

51138778871 is a deficient number, since it is larger than the sum of its proper divisors (3008163481).

51138778871 is a wasteful number, since it uses less digits than its factorization.

51138778871 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3008163480.

The product of its digits is 2634240, while the sum is 56.

The spelling of 51138778871 in words is "fifty-one billion, one hundred thirty-eight million, seven hundred seventy-eight thousand, eight hundred seventy-one".