821449221768 has 108 divisors (see below), whose sum is σ = 2588153770215. Its totient is φ = 234684396576.

The previous prime is 821449221743. The next prime is 821449221781. The reversal of 821449221768 is 867122944128.

It is a powerful number, because all its prime factors have an exponent greater than 1 and also an Achilles number because it is not a perfect power.

821449221768 is a `hidden beast` number, since 8 + 2 + 1 + 449 + 22 + 176 + 8 = 666.

It can be written as a sum of positive squares in only one way, i.e., 410724610884 + 410724610884 = 640878^2 + 640878^2 .

It is an ABA number since it can be written as A⋅B^A, here for A=2, B=640878.

It is a nude number because it is divisible by every one of its digits.

It is an unprimeable number.

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 in 26 ways as a sum of consecutive naturals, for example, 53826123 + ... + 53841381.

Almost surely, 2^821449221768 is an apocalyptic number.

It is an amenable number.

821449221768 is an abundant number, since it is smaller than the sum of its proper divisors (1766704548447).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

821449221768 is an equidigital number, since it uses as much as digits as its factorization.

821449221768 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 30544 (or 15271 counting only the distinct ones).

The product of its digits is 3096576, while the sum is 54.

The spelling of 821449221768 in words is "eight hundred twenty-one billion, four hundred forty-nine million, two hundred twenty-one thousand, seven hundred sixty-eight".