878221 has 2 divisors, whose sum is σ = 878222. Its totient is φ = 878220.

The previous prime is 878201. The next prime is 878239. The reversal of 878221 is 122878.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 741321 + 136900 = 861^2 + 370^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-878221 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 878221.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (878201) 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, 439110 + 439111.

It is an arithmetic number, because the mean of its divisors is an integer number (439111).

2⁸⁷⁸²²¹ is an apocalyptic number.

It is an amenable number.

878221 is a deficient number, since it is larger than the sum of its proper divisors (1).

878221 is an equidigital number, since it uses as much as digits as its factorization.

878221 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1792, while the sum is 28.

The square root of 878221 is about 937.1344620704. The cubic root of 878221 is about 95.7637783052.

The spelling of 878221 in words is "eight hundred seventy-eight thousand, two hundred twenty-one".