821365707904 has 32 divisors (see below), whose sum is σ = 1870073712000. Its totient is φ = 352013874432.

The previous prime is 821365707817. The next prime is 821365707923. The reversal of 821365707904 is 409707563128.

It is a tau number, because it is divible by the number of its divisors (32).

It is a super-2 number, since 2×821365707904² (a number of 25 digits) contains 22 as substring.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 458350504 + ... + 458352295.

It is an arithmetic number, because the mean of its divisors is an integer number (58439803500).

It is a 1-persistent number, because it is pandigital, but 2⋅821365707904 = 1642731415808 is not.

Almost surely, 2^821365707904 is an apocalyptic number.

It is an amenable number.

821365707904 is an abundant number, since it is smaller than the sum of its proper divisors (1048708004096).

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

821365707904 is an equidigital number, since it uses as much as digits as its factorization.

821365707904 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 916702820 (or 916702808 counting only the distinct ones).

The product of its (nonzero) digits is 2540160, while the sum is 52.

The spelling of 821365707904 in words is "eight hundred twenty-one billion, three hundred sixty-five million, seven hundred seven thousand, nine hundred four".