821489 has 2 divisors, whose sum is σ = 821490. Its totient is φ = 821488.

The previous prime is 821479. The next prime is 821497. The reversal of 821489 is 984128.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 774400 + 47089 = 880^2 + 217^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-821489 is a prime.

It is an Ulam number.

It is not a weakly prime, because it can be changed into another prime (821449) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 410744 + 410745.

It is an arithmetic number, because the mean of its divisors is an integer number (410745).

2⁸²¹⁴⁸⁹ is an apocalyptic number.

It is an amenable number.

821489 is a deficient number, since it is larger than the sum of its proper divisors (1).

821489 is an equidigital number, since it uses as much as digits as its factorization.

821489 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 4608, while the sum is 32.

The square root of 821489 is about 906.3603036321. The cubic root of 821489 is about 93.6556360128.

The spelling of 821489 in words is "eight hundred twenty-one thousand, four hundred eighty-nine".