721007730 has 192 divisors, whose sum is σ = 2037934080. Its totient is φ = 183259584.

The previous prime is 721007719. The next prime is 721007737. The reversal of 721007730 is 37700127.

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

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 721007694 and 721007703.

It is not an unprimeable number, because it can be changed into a prime (721007737) 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 95 ways as a sum of consecutive naturals, for example, 6738337 + ... + 6738443.

It is an arithmetic number, because the mean of its divisors is an integer number (10614240).

Almost surely, 2^721007730 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 721007730, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1018967040).

721007730 is an abundant number, since it is smaller than the sum of its proper divisors (1316926350).

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

721007730 is a wasteful number, since it uses less digits than its factorization.

721007730 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 235 (or 223 counting only the distinct ones).

The product of its (nonzero) digits is 2058, while the sum is 27.

The square root of 721007730 is about 26851.5871039311. The cubic root of 721007730 is about 896.6989067854.

Adding to 721007730 its reverse (37700127), we get a palindrome (758707857).

The spelling of 721007730 in words is "seven hundred twenty-one million, seven thousand, seven hundred thirty".