51821717 has 2 divisors, whose sum is σ = 51821718. Its totient is φ = 51821716.

The previous prime is 51821713. The next prime is 51821723. The reversal of 51821717 is 71712815.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 46977316 + 4844401 = 6854^2 + 2201^2 .

It is a cyclic number.

It is not a de Polignac number, because 51821717 - 2² = 51821713 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (51821713) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 25910858 + 25910859.

It is an arithmetic number, because the mean of its divisors is an integer number (25910859).

Almost surely, 2^51821717 is an apocalyptic number.

It is an amenable number.

51821717 is a deficient number, since it is larger than the sum of its proper divisors (1).

51821717 is an equidigital number, since it uses as much as digits as its factorization.

51821717 is an evil number, because the sum of its binary digits is even.

The product of its digits is 3920, while the sum is 32.

The square root of 51821717 is about 7198.7302352568. The cubic root of 51821717 is about 372.8240610449.

The spelling of 51821717 in words is "fifty-one million, eight hundred twenty-one thousand, seven hundred seventeen".