51686717 has 4 divisors (see below), whose sum is σ = 51918720. Its totient is φ = 51454716.

The previous prime is 51686711. The next prime is 51686779. The reversal of 51686717 is 71768615.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 71768615 = 5 ⋅14353723.

It is a cyclic number.

It is not a de Polignac number, because 51686717 - 2¹⁰ = 51685693 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51686711) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 115667 + ... + 116112.

It is an arithmetic number, because the mean of its divisors is an integer number (12979680).

Almost surely, 2^51686717 is an apocalyptic number.

It is an amenable number.

51686717 is a deficient number, since it is larger than the sum of its proper divisors (232003).

51686717 is a wasteful number, since it uses less digits than its factorization.

51686717 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 232002.

The product of its digits is 70560, while the sum is 41.

The square root of 51686717 is about 7189.3474669124. The cubic root of 51686717 is about 372.5000333318.

The spelling of 51686717 in words is "fifty-one million, six hundred eighty-six thousand, seven hundred seventeen".