821209084805 has 8 divisors (see below), whose sum is σ = 987410051712. Its totient is φ = 655661167888.

The previous prime is 821209084769. The next prime is 821209084807. The reversal of 821209084805 is 508480902128.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 821209084805 - 2³⁰ = 820135342981 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 821209084805.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (821209084807) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 163259729 + ... + 163264758.

It is an arithmetic number, because the mean of its divisors is an integer number (123426256464).

Almost surely, 2^821209084805 is an apocalyptic number.

It is an amenable number.

821209084805 is a deficient number, since it is larger than the sum of its proper divisors (166200966907).

821209084805 is a wasteful number, since it uses less digits than its factorization.

821209084805 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 326524995.

The product of its (nonzero) digits is 368640, while the sum is 47.

The spelling of 821209084805 in words is "eight hundred twenty-one billion, two hundred nine million, eighty-four thousand, eight hundred five".