51720118656 has 32 divisors (see below), whose sum is σ = 137381566200. Its totient is φ = 17240039424.

The previous prime is 51720118573. The next prime is 51720118661. The reversal of 51720118656 is 65681102715.

It is a tau number, because it is divible by the number of its divisors (32).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 67343521 + ... + 67344288.

Almost surely, 2^51720118656 is an apocalyptic number.

It is an amenable number.

51720118656 is an abundant number, since it is smaller than the sum of its proper divisors (85661447544).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

51720118656 is a wasteful number, since it uses less digits than its factorization.

51720118656 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 134687826 (or 134687814 counting only the distinct ones).

The product of its (nonzero) digits is 100800, while the sum is 42.

The spelling of 51720118656 in words is "fifty-one billion, seven hundred twenty million, one hundred eighteen thousand, six hundred fifty-six".