51312917 has 4 divisors (see below), whose sum is σ = 51348780. Its totient is φ = 51277056.

The previous prime is 51312913. The next prime is 51312929. The reversal of 51312917 is 71921315.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 71921315 = 5 ⋅14384263.

It can be written as a sum of positive squares in 2 ways, for example, as 48246916 + 3066001 = 6946^2 + 1751^2 .

It is a cyclic number.

It is not a de Polignac number, because 51312917 - 2² = 51312913 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 51312917.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51312913) 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, 15692 + ... + 18677.

It is an arithmetic number, because the mean of its divisors is an integer number (12837195).

Almost surely, 2^51312917 is an apocalyptic number.

It is an amenable number.

51312917 is a deficient number, since it is larger than the sum of its proper divisors (35863).

51312917 is a wasteful number, since it uses less digits than its factorization.

51312917 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 35862.

The product of its digits is 1890, while the sum is 29.

The square root of 51312917 is about 7163.3034976888. The cubic root of 51312917 is about 371.5998824505.

The spelling of 51312917 in words is "fifty-one million, three hundred twelve thousand, nine hundred seventeen".