721747620 has 144 divisors (see below), whose sum is σ = 2396459520. Its totient is φ = 174374400.

The previous prime is 721747591. The next prime is 721747627. The reversal of 721747620 is 26747127.

It is a happy number.

721747620 is a `hidden beast` number, since 7 + 21 + 7 + 4 + 7 + 620 = 666.

721747620 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is not an unprimeable number, because it can be changed into a prime (721747627) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 948040 + ... + 948800.

It is an arithmetic number, because the mean of its divisors is an integer number (16642080).

Almost surely, 2^721747620 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 721747620, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1198229760).

721747620 is an abundant number, since it is smaller than the sum of its proper divisors (1674711900).

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

721747620 is a wasteful number, since it uses less digits than its factorization.

721747620 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1266 (or 1261 counting only the distinct ones).

The product of its (nonzero) digits is 32928, while the sum is 36.

The square root of 721747620 is about 26865.3609690992. The cubic root of 721747620 is about 897.0055293597.

The spelling of 721747620 in words is "seven hundred twenty-one million, seven hundred forty-seven thousand, six hundred twenty".