821808145602 has 64 divisors (see below), whose sum is σ = 1858074289920. Its totient is φ = 269170128000.

The previous prime is 821808145601. The next prime is 821808145607. The reversal of 821808145602 is 206541808128.

821808145602 is a `hidden beast` number, since 8 + 2 + 1 + 8 + 0 + 81 + 4 + 560 + 2 = 666.

It is not an unprimeable number, because it can be changed into a prime (821808145601) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 3111102 + ... + 3364902.

It is an arithmetic number, because the mean of its divisors is an integer number (29032410780).

Almost surely, 2^821808145602 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 821808145602, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (929037144960).

821808145602 is an abundant number, since it is smaller than the sum of its proper divisors (1036266144318).

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

821808145602 is a wasteful number, since it uses less digits than its factorization.

821808145602 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 254856 (or 254850 counting only the distinct ones).

The product of its (nonzero) digits is 245760, while the sum is 45.

The spelling of 821808145602 in words is "eight hundred twenty-one billion, eight hundred eight million, one hundred forty-five thousand, six hundred two".