821827463209 has 9 divisors (see below), whose sum is σ = 867376249623. Its totient is φ = 778557068352.

The previous prime is 821827463129. The next prime is 821827463231. The reversal of 821827463209 is 902364728128.

The square root of 821827463209 is 906547.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in only one way, i.e., 80630442025 + 741197021184 = 283955^2 + 860928^2 .

It is a de Polignac number, because none of the positive numbers 2^k-821827463209 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (821827463279) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 17200537 + ... + 17248249.

It is an arithmetic number, because the mean of its divisors is an integer number (96375138847).

Almost surely, 2^821827463209 is an apocalyptic number.

821827463209 is the 906547-th square number.

821827463209 is the 453274-th centered octagonal number.

It is an amenable number.

821827463209 is a deficient number, since it is larger than the sum of its proper divisors (45548786414).

821827463209 is an frugal number, since it uses more digits than its factorization.

821827463209 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 95464 (or 47732 counting only the distinct ones).

The product of its (nonzero) digits is 2322432, while the sum is 52.

The spelling of 821827463209 in words is "eight hundred twenty-one billion, eight hundred twenty-seven million, four hundred sixty-three thousand, two hundred nine".