347821 has 2 divisors, whose sum is σ = 347822. Its totient is φ = 347820.

The previous prime is 347813. The next prime is 347849. The reversal of 347821 is 128743.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 346921 + 900 = 589^2 + 30^2 .

It is a cyclic number.

It is not a de Polignac number, because 347821 - 2³ = 347813 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (347801) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 173910 + 173911.

It is an arithmetic number, because the mean of its divisors is an integer number (173911).

2³⁴⁷⁸²¹ is an apocalyptic number.

347821 is the 341-st hex number.

It is an amenable number.

347821 is a deficient number, since it is larger than the sum of its proper divisors (1).

347821 is an equidigital number, since it uses as much as digits as its factorization.

347821 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1344, while the sum is 25.

The square root of 347821 is about 589.7635119266. The cubic root of 347821 is about 70.3264345387.

The spelling of 347821 in words is "three hundred forty-seven thousand, eight hundred twenty-one".