721655785280 has 112 divisors (see below), whose sum is σ = 1774292981760. Its totient is φ = 279285043200.

The previous prime is 721655785271. The next prime is 721655785289. The reversal of 721655785280 is 82587556127.

It is an interprime number because it is at equal distance from previous prime (721655785271) and next prime (721655785289).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (721655785289) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 80456636 + ... + 80465604.

Almost surely, 2^721655785280 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 721655785280, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (887146490880).

721655785280 is an abundant number, since it is smaller than the sum of its proper divisors (1052637196480).

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

721655785280 is a wasteful number, since it uses less digits than its factorization.

721655785280 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17128 (or 17118 counting only the distinct ones).

The product of its (nonzero) digits is 9408000, while the sum is 56.

The spelling of 721655785280 in words is "seven hundred twenty-one billion, six hundred fifty-five million, seven hundred eighty-five thousand, two hundred eighty".