721501720 has 64 divisors (see below), whose sum is σ = 1726038720. Its totient is φ = 270825984.

The previous prime is 721501679. The next prime is 721501721. The reversal of 721501720 is 27105127.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (721501721) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 41362 + ... + 56158.

It is an arithmetic number, because the mean of its divisors is an integer number (26969355).

Almost surely, 2^721501720 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 721501720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (863019360).

721501720 is an abundant number, since it is smaller than the sum of its proper divisors (1004537000).

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

721501720 is a wasteful number, since it uses less digits than its factorization.

721501720 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14884 (or 14880 counting only the distinct ones).

The product of its (nonzero) digits is 980, while the sum is 25.

The square root of 721501720 is about 26860.7840540815. The cubic root of 721501720 is about 896.9036476178.

Adding to 721501720 its reverse (27105127), we get a palindrome (748606847).

The spelling of 721501720 in words is "seven hundred twenty-one million, five hundred one thousand, seven hundred twenty".