542821 has 2 divisors, whose sum is σ = 542822. Its totient is φ = 542820.

The previous prime is 542797. The next prime is 542831. The reversal of 542821 is 128245.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 497025 + 45796 = 705^2 + 214^2 .

It is a cyclic number.

It is not a de Polignac number, because 542821 - 2⁷ = 542693 is a prime.

542821 is a lucky number.

It is a junction number, because it is equal to n+sod(n) for n = 542792 and 542801.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (542831) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 271410 + 271411.

It is an arithmetic number, because the mean of its divisors is an integer number (271411).

2⁵⁴²⁸²¹ is an apocalyptic number.

It is an amenable number.

542821 is a deficient number, since it is larger than the sum of its proper divisors (1).

542821 is an equidigital number, since it uses as much as digits as its factorization.

542821 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 640, while the sum is 22.

The square root of 542821 is about 736.7638699068. The cubic root of 542821 is about 81.5740854689.

The spelling of 542821 in words is "five hundred forty-two thousand, eight hundred twenty-one".