721513320 has 384 divisors, whose sum is σ = 2619993600. Its totient is φ = 158146560.

The previous prime is 721513267. The next prime is 721513339. The reversal of 721513320 is 23315127.

It is a Cunningham number, because it is equal to 26861²-1.

It is a Harshad number since it is a multiple of its sum of digits (24).

It is an unprimeable number.

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 95 ways as a sum of consecutive naturals, for example, 9133041 + ... + 9133119.

It is an arithmetic number, because the mean of its divisors is an integer number (6822900).

Almost surely, 2^721513320 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 721513320, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1309996800).

721513320 is an abundant number, since it is smaller than the sum of its proper divisors (1898480280).

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

721513320 is a wasteful number, since it uses less digits than its factorization.

721513320 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 169 (or 154 counting only the distinct ones).

The product of its (nonzero) digits is 1260, while the sum is 24.

The square root of 721513320 is about 26860.9999813857. Note that the first 4 decimals coincide. The cubic root of 721513320 is about 896.9084542714.

Adding to 721513320 its reverse (23315127), we get a palindrome (744828447).

The spelling of 721513320 in words is "seven hundred twenty-one million, five hundred thirteen thousand, three hundred twenty".