516205421 has 2 divisors, whose sum is σ = 516205422. Its totient is φ = 516205420.

The previous prime is 516205387. The next prime is 516205447. The reversal of 516205421 is 124502615.

It is an a-pointer prime, because the next prime (516205447) can be obtained adding 516205421 to its sum of digits (26).

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 385926025 + 130279396 = 19645^2 + 11414^2 .

It is a cyclic number.

It is not a de Polignac number, because 516205421 - 2¹⁰ = 516204397 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (516207421) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 258102710 + 258102711.

It is an arithmetic number, because the mean of its divisors is an integer number (258102711).

Almost surely, 2^516205421 is an apocalyptic number.

It is an amenable number.

516205421 is a deficient number, since it is larger than the sum of its proper divisors (1).

516205421 is an equidigital number, since it uses as much as digits as its factorization.

516205421 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2400, while the sum is 26.

The square root of 516205421 is about 22720.1545109183. The cubic root of 516205421 is about 802.1843537575.

The spelling of 516205421 in words is "five hundred sixteen million, two hundred five thousand, four hundred twenty-one".