51636778765 has 16 divisors (see below), whose sum is σ = 72797026176. Its totient is φ = 34665249600.

The previous prime is 51636778759. The next prime is 51636778783. The reversal of 51636778765 is 56787763615.

It is a happy number.

It is not a de Polignac number, because 51636778765 - 2¹¹ = 51636776717 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

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 15 ways as a sum of consecutive naturals, for example, 36108921 + ... + 36110350.

It is an arithmetic number, because the mean of its divisors is an integer number (4549814136).

Almost surely, 2^51636778765 is an apocalyptic number.

51636778765 is a gapful number since it is divisible by the number (55) formed by its first and last digit.

It is an amenable number.

51636778765 is a deficient number, since it is larger than the sum of its proper divisors (21160247411).

51636778765 is a wasteful number, since it uses less digits than its factorization.

51636778765 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 72219300.

The product of its digits is 44452800, while the sum is 61.

The spelling of 51636778765 in words is "fifty-one billion, six hundred thirty-six million, seven hundred seventy-eight thousand, seven hundred sixty-five".