721345500 has 168 divisors, whose sum is σ = 2363240880. Its totient is φ = 192261600.

The previous prime is 721345463. The next prime is 721345523. The reversal of 721345500 is 5543127.

It is a happy number.

It is a super-3 number, since 3×721345500³ (a number of 28 digits) contains 333 as substring.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 55 ways as a sum of consecutive naturals, for example, 363511 + ... + 365489.

It is an arithmetic number, because the mean of its divisors is an integer number (14066910).

Almost surely, 2^721345500 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 721345500, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1181620440).

721345500 is an abundant number, since it is smaller than the sum of its proper divisors (1641895380).

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

721345500 is a wasteful number, since it uses less digits than its factorization.

721345500 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2016 (or 1989 counting only the distinct ones).

The product of its (nonzero) digits is 4200, while the sum is 27.

The square root of 721345500 is about 26857.8759398430. The cubic root of 721345500 is about 896.8389102338.

Adding to 721345500 its reverse (5543127), we get a palindrome (726888627).

The spelling of 721345500 in words is "seven hundred twenty-one million, three hundred forty-five thousand, five hundred".