356821 has 2 divisors, whose sum is σ = 356822. Its totient is φ = 356820.

The previous prime is 356819. The next prime is 356831. The reversal of 356821 is 128653.

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., 260100 + 96721 = 510^2 + 311^2 .

It is a cyclic number.

It is not a de Polignac number, because 356821 - 2¹ = 356819 is a prime.

Together with 356819, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (356831) 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, 178410 + 178411.

It is an arithmetic number, because the mean of its divisors is an integer number (178411).

2³⁵⁶⁸²¹ is an apocalyptic number.

It is an amenable number.

356821 is a deficient number, since it is larger than the sum of its proper divisors (1).

356821 is an equidigital number, since it uses as much as digits as its factorization.

356821 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1440, while the sum is 25.

The square root of 356821 is about 597.3449589642. The cubic root of 356821 is about 70.9278510620.

The spelling of 356821 in words is "three hundred fifty-six thousand, eight hundred twenty-one".