821210447 has 2 divisors, whose sum is σ = 821210448. Its totient is φ = 821210446.

The previous prime is 821210407. The next prime is 821210473. The reversal of 821210447 is 744012128.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-821210447 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (821210407) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 410605223 + 410605224.

It is an arithmetic number, because the mean of its divisors is an integer number (410605224).

Almost surely, 2^821210447 is an apocalyptic number.

821210447 is a deficient number, since it is larger than the sum of its proper divisors (1).

821210447 is an equidigital number, since it uses as much as digits as its factorization.

821210447 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 3584, while the sum is 29.

The square root of 821210447 is about 28656.7696539579. The cubic root of 821210447 is about 936.4504913640.

The spelling of 821210447 in words is "eight hundred twenty-one million, two hundred ten thousand, four hundred forty-seven".