51688921965 has 8 divisors (see below), whose sum is σ = 82702275168. Its totient is φ = 27567425040.

The previous prime is 51688921943. The next prime is 51688921969. The reversal of 51688921965 is 56912988615.

51688921965 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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

It is not a de Polignac number, because 51688921965 - 2⁶ = 51688921901 is a prime.

It is a super-2 number, since 2×51688921965² (a number of 22 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 51688921899 and 51688921908.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51688921969) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1722964051 + ... + 1722964080.

It is an arithmetic number, because the mean of its divisors is an integer number (10337784396).

Almost surely, 2^51688921965 is an apocalyptic number.

It is an amenable number.

51688921965 is a deficient number, since it is larger than the sum of its proper divisors (31013353203).

51688921965 is a wasteful number, since it uses less digits than its factorization.

51688921965 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3445928139.

The product of its digits is 9331200, while the sum is 60.

The spelling of 51688921965 in words is "fifty-one billion, six hundred eighty-eight million, nine hundred twenty-one thousand, nine hundred sixty-five".