821278847 has 2 divisors, whose sum is σ = 821278848. Its totient is φ = 821278846.

The previous prime is 821278841. The next prime is 821278849. The reversal of 821278847 is 748872128.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 821278847 - 2¹⁶ = 821213311 is a prime.

Together with 821278849, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (821278841) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 410639423 + 410639424.

It is an arithmetic number, because the mean of its divisors is an integer number (410639424).

Almost surely, 2^821278847 is an apocalyptic number.

821278847 is a deficient number, since it is larger than the sum of its proper divisors (1).

821278847 is an equidigital number, since it uses as much as digits as its factorization.

821278847 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 401408, while the sum is 47.

The square root of 821278847 is about 28657.9630643910. The cubic root of 821278847 is about 936.4764901546.

The spelling of 821278847 in words is "eight hundred twenty-one million, two hundred seventy-eight thousand, eight hundred forty-seven".