721139220 has 96 divisors (see below), whose sum is σ = 2248444800. Its totient is φ = 191884032.

The previous prime is 721139207. The next prime is 721139227. The reversal of 721139220 is 22931127.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (721139227) by changing a digit.

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 31 ways as a sum of consecutive naturals, for example, 306087 + ... + 308433.

It is an arithmetic number, because the mean of its divisors is an integer number (23421300).

Almost surely, 2^721139220 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 721139220, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1124222400).

721139220 is an abundant number, since it is smaller than the sum of its proper divisors (1527305580).

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

721139220 is a wasteful number, since it uses less digits than its factorization.

721139220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2934 (or 2926 counting only the distinct ones).

The product of its (nonzero) digits is 1512, while the sum is 27.

The square root of 721139220 is about 26854.0354509336. The cubic root of 721139220 is about 896.7534137241.

The spelling of 721139220 in words is "seven hundred twenty-one million, one hundred thirty-nine thousand, two hundred twenty".