51708821 has 2 divisors, whose sum is σ = 51708822. Its totient is φ = 51708820.

The previous prime is 51708817. The next prime is 51708851. The reversal of 51708821 is 12880715.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 51638596 + 70225 = 7186^2 + 265^2 .

It is a cyclic number.

It is not a de Polignac number, because 51708821 - 2² = 51708817 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 (51708851) by changing a digit.

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 as a sum of consecutive naturals, namely, 25854410 + 25854411.

It is an arithmetic number, because the mean of its divisors is an integer number (25854411).

Almost surely, 2^51708821 is an apocalyptic number.

It is an amenable number.

51708821 is a deficient number, since it is larger than the sum of its proper divisors (1).

51708821 is an equidigital number, since it uses as much as digits as its factorization.

51708821 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 4480, while the sum is 32.

The square root of 51708821 is about 7190.8845770183. The cubic root of 51708821 is about 372.5531260654.

The spelling of 51708821 in words is "fifty-one million, seven hundred eight thousand, eight hundred twenty-one".