342821 has 2 divisors, whose sum is σ = 342822. Its totient is φ = 342820.

The previous prime is 342803. The next prime is 342833. The reversal of 342821 is 128243.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 297025 + 45796 = 545^2 + 214^2 .

It is a cyclic number.

It is not a de Polignac number, because 342821 - 2⁶ = 342757 is a prime.

It is a Chen prime.

It is an Ulam number.

It is a junction number, because it is equal to n+sod(n) for n = 342793 and 342802.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 342821.

It is not a weakly prime, because it can be changed into another prime (342841) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 171410 + 171411.

It is an arithmetic number, because the mean of its divisors is an integer number (171411).

2³⁴²⁸²¹ is an apocalyptic number.

It is an amenable number.

342821 is a deficient number, since it is larger than the sum of its proper divisors (1).

342821 is an equidigital number, since it uses as much as digits as its factorization.

342821 is an evil number, because the sum of its binary digits is even.

The product of its digits is 384, while the sum is 20.

The square root of 342821 is about 585.5091801159. The cubic root of 342821 is about 69.9878210104.

It can be divided in two parts, 3 and 42821, that added together give a palindrome (42824).

The spelling of 342821 in words is "three hundred forty-two thousand, eight hundred twenty-one".