721680650 has 24 divisors (see below), whose sum is σ = 1343979084. Its totient is φ = 288316800.

The previous prime is 721680611. The next prime is 721680677. The reversal of 721680650 is 56086127.

It can be written as a sum of positive squares in 6 ways, for example, as 156525121 + 565155529 = 12511^2 + 23773^2 .

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 721680650.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 34190 + ... + 51110.

Almost surely, 2^721680650 is an apocalyptic number.

721680650 is a deficient number, since it is larger than the sum of its proper divisors (622298434).

721680650 is a wasteful number, since it uses less digits than its factorization.

721680650 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17786 (or 17781 counting only the distinct ones).

The product of its (nonzero) digits is 20160, while the sum is 35.

The square root of 721680650 is about 26864.1145396605. The cubic root of 721680650 is about 896.9777845189.

The spelling of 721680650 in words is "seven hundred twenty-one million, six hundred eighty thousand, six hundred fifty".