721171220 has 192 divisors, whose sum is σ = 2032128000. Its totient is φ = 212526720.

The previous prime is 721171117. The next prime is 721171223. The reversal of 721171220 is 22171127.

721171220 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (721171223) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 1433489 + ... + 1433991.

It is an arithmetic number, because the mean of its divisors is an integer number (10584000).

Almost surely, 2^721171220 is an apocalyptic number.

721171220 is a gapful number since it is divisible by the number (70) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 721171220, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1016064000).

721171220 is an abundant number, since it is smaller than the sum of its proper divisors (1310956780).

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

721171220 is a wasteful number, since it uses less digits than its factorization.

721171220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 563 (or 547 counting only the distinct ones).

The product of its (nonzero) digits is 392, while the sum is 23.

The square root of 721171220 is about 26854.6312579413. The cubic root of 721171220 is about 896.7666777763.

It can be divided in two parts, 72117 and 1220, that added together give a palindrome (73337).

The spelling of 721171220 in words is "seven hundred twenty-one million, one hundred seventy-one thousand, two hundred twenty".