721529217240 has 768 divisors, whose sum is σ = 2577630988800. Its totient is φ = 160138321920.

The previous prime is 721529217173. The next prime is 721529217251. The reversal of 721529217240 is 42712925127.

It is a super-2 number, since 2×721529217240² (a number of 25 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 721529217192 and 721529217201.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 191 ways as a sum of consecutive naturals, for example, 2079334747 + ... + 2079335093.

It is an arithmetic number, because the mean of its divisors is an integer number (3356290350).

Almost surely, 2^721529217240 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 721529217240, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1288815494400).

721529217240 is an abundant number, since it is smaller than the sum of its proper divisors (1856101771560).

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

721529217240 is a wasteful number, since it uses less digits than its factorization.

721529217240 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 528 (or 493 counting only the distinct ones).

The product of its (nonzero) digits is 141120, while the sum is 42.

The spelling of 721529217240 in words is "seven hundred twenty-one billion, five hundred twenty-nine million, two hundred seventeen thousand, two hundred forty".