721281380 has 48 divisors (see below), whose sum is σ = 1589462784. Its totient is φ = 274412160.

The previous prime is 721281361. The next prime is 721281397. The reversal of 721281380 is 83182127.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 78929 + ... + 87591.

It is an arithmetic number, because the mean of its divisors is an integer number (33113808).

Almost surely, 2^721281380 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 721281380, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (794731392).

721281380 is an abundant number, since it is smaller than the sum of its proper divisors (868181404).

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

721281380 is a wasteful number, since it uses less digits than its factorization.

721281380 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8876 (or 8874 counting only the distinct ones).

The product of its (nonzero) digits is 5376, while the sum is 32.

The square root of 721281380 is about 26856.6822224935. The cubic root of 721281380 is about 896.8123362759.

The spelling of 721281380 in words is "seven hundred twenty-one million, two hundred eighty-one thousand, three hundred eighty".