516421 has 2 divisors, whose sum is σ = 516422. Its totient is φ = 516420.

The previous prime is 516407. The next prime is 516431. The reversal of 516421 is 124615.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 504100 + 12321 = 710^2 + 111^2 .

It is a cyclic number.

It is not a de Polignac number, because 516421 - 2⁷ = 516293 is a prime.

516421 is a lucky number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (516431) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 258210 + 258211.

It is an arithmetic number, because the mean of its divisors is an integer number (258211).

2⁵¹⁶⁴²¹ is an apocalyptic number.

It is an amenable number.

516421 is a deficient number, since it is larger than the sum of its proper divisors (1).

516421 is an equidigital number, since it uses as much as digits as its factorization.

516421 is an evil number, because the sum of its binary digits is even.

The product of its digits is 240, while the sum is 19.

The square root of 516421 is about 718.6243803267. The cubic root of 516421 is about 80.2296008295.

The spelling of 516421 in words is "five hundred sixteen thousand, four hundred twenty-one".