516564821 has 2 divisors, whose sum is σ = 516564822. Its totient is φ = 516564820.

The previous prime is 516564793. The next prime is 516564869. The reversal of 516564821 is 128465615.

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., 403567921 + 112996900 = 20089^2 + 10630^2 .

It is a cyclic number.

It is not a de Polignac number, because 516564821 - 2⁶ = 516564757 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 (516564421) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 258282410 + 258282411.

It is an arithmetic number, because the mean of its divisors is an integer number (258282411).

Almost surely, 2^516564821 is an apocalyptic number.

It is an amenable number.

516564821 is a deficient number, since it is larger than the sum of its proper divisors (1).

516564821 is an equidigital number, since it uses as much as digits as its factorization.

516564821 is an evil number, because the sum of its binary digits is even.

The product of its digits is 57600, while the sum is 38.

The square root of 516564821 is about 22728.0624119171. The cubic root of 516564821 is about 802.3704800305.

The spelling of 516564821 in words is "five hundred sixteen million, five hundred sixty-four thousand, eight hundred twenty-one".