72821721024 has 336 divisors, whose sum is σ = 229470984288. Its totient is φ = 21944991744.

The previous prime is 72821721001. The next prime is 72821721047. The reversal of 72821721024 is 42012712827.

It is a Cunningham number, because it is equal to 269855²-1.

It is an interprime number because it is at equal distance from previous prime (72821721001) and next prime (72821721047).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a self number, because there is not a number n which added to its sum of digits gives 72821721024.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 77717484 + ... + 77718420.

It is an arithmetic number, because the mean of its divisors is an integer number (682949358).

Almost surely, 2^72821721024 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 72821721024, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (114735492144).

72821721024 is an abundant number, since it is smaller than the sum of its proper divisors (156649263264).

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

72821721024 is a wasteful number, since it uses less digits than its factorization.

72821721024 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1172 (or 1159 counting only the distinct ones).

The product of its (nonzero) digits is 25088, while the sum is 36.

The spelling of 72821721024 in words is "seventy-two billion, eight hundred twenty-one million, seven hundred twenty-one thousand, twenty-four".