821144451072 has 384 divisors, whose sum is σ = 2428538112000. Its totient is φ = 244667351040.

The previous prime is 821144451067. The next prime is 821144451089. The reversal of 821144451072 is 270154441128.

It is a tau number, because it is divible by the number of its divisors (384).

It is a self number, because there is not a number n which added to its sum of digits gives 821144451072.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 1246045879 + ... + 1246046537.

It is an arithmetic number, because the mean of its divisors is an integer number (6324318000).

Almost surely, 2^821144451072 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 821144451072, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1214269056000).

821144451072 is an abundant number, since it is smaller than the sum of its proper divisors (1607393660928).

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

821144451072 is a wasteful number, since it uses less digits than its factorization.

821144451072 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 977 (or 957 counting only the distinct ones).

The product of its (nonzero) digits is 71680, while the sum is 39.

The spelling of 821144451072 in words is "eight hundred twenty-one billion, one hundred forty-four million, four hundred fifty-one thousand, seventy-two".