721531650 has 192 divisors, whose sum is σ = 2192716800. Its totient is φ = 153342720.

The previous prime is 721531649. The next prime is 721531661. The reversal of 721531650 is 56135127.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a Curzon number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 1176744 + ... + 1177356.

It is an arithmetic number, because the mean of its divisors is an integer number (11420400).

Almost surely, 2^721531650 is an apocalyptic number.

721531650 is a gapful number since it is divisible by the number (70) formed by its first and last digit.

It is a practical number, because each smaller number is the sum of distinct divisors of 721531650, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1096358400).

721531650 is an abundant number, since it is smaller than the sum of its proper divisors (1471185150).

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

721531650 is a wasteful number, since it uses less digits than its factorization.

721531650 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 713 (or 708 counting only the distinct ones).

The product of its (nonzero) digits is 6300, while the sum is 30.

The square root of 721531650 is about 26861.3411802166. The cubic root of 721531650 is about 896.9160495078.

Adding to 721531650 its reverse (56135127), we get a palindrome (777666777).

The spelling of 721531650 in words is "seven hundred twenty-one million, five hundred thirty-one thousand, six hundred fifty".