516721 has 2 divisors, whose sum is σ = 516722. Its totient is φ = 516720.

The previous prime is 516713. The next prime is 516727. The reversal of 516721 is 127615.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 404496 + 112225 = 636^2 + 335^2 .

It is a cyclic number.

It is not a de Polignac number, because 516721 - 2³ = 516713 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 516692 and 516701.

It is not a weakly prime, because it can be changed into another prime (516727) 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, 258360 + 258361.

It is an arithmetic number, because the mean of its divisors is an integer number (258361).

2⁵¹⁶⁷²¹ is an apocalyptic number.

It is an amenable number.

516721 is a deficient number, since it is larger than the sum of its proper divisors (1).

516721 is an equidigital number, since it uses as much as digits as its factorization.

516721 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 420, while the sum is 22.

The square root of 516721 is about 718.8330821547. The cubic root of 516721 is about 80.2451335189.

The spelling of 516721 in words is "five hundred sixteen thousand, seven hundred twenty-one".