821976318720 has 576 divisors, whose sum is σ = 3188153364480. Its totient is φ = 199640678400.

The previous prime is 821976318677. The next prime is 821976318733. The reversal of 821976318720 is 27813679128.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (576).

It is a Harshad number since it is a multiple of its sum of digits (54).

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 18190555 + ... + 18235685.

It is an arithmetic number, because the mean of its divisors is an integer number (5534988480).

Almost surely, 2^821976318720 is an apocalyptic number.

821976318720 is a gapful number since it is divisible by the number (80) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 821976318720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1594076682240).

821976318720 is an abundant number, since it is smaller than the sum of its proper divisors (2366177045760).

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

821976318720 is a wasteful number, since it uses less digits than its factorization.

821976318720 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 45209 (or 45189 counting only the distinct ones).

The product of its (nonzero) digits is 2032128, while the sum is 54.

The spelling of 821976318720 in words is "eight hundred twenty-one billion, nine hundred seventy-six million, three hundred eighteen thousand, seven hundred twenty".