721304645 has 16 divisors (see below), whose sum is σ = 917801280. Its totient is φ = 542317824.

The previous prime is 721304641. The next prime is 721304671. The reversal of 721304645 is 546403127.

It is a cyclic number.

It is not a de Polignac number, because 721304645 - 2² = 721304641 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (721304641) 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 15 ways as a sum of consecutive naturals, for example, 57074 + ... + 68556.

It is an arithmetic number, because the mean of its divisors is an integer number (57362580).

Almost surely, 2^721304645 is an apocalyptic number.

It is an amenable number.

721304645 is a deficient number, since it is larger than the sum of its proper divisors (196496635).

721304645 is a wasteful number, since it uses less digits than its factorization.

721304645 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12244.

The product of its (nonzero) digits is 20160, while the sum is 32.

The square root of 721304645 is about 26857.1153514297. The cubic root of 721304645 is about 896.8219784282.

The spelling of 721304645 in words is "seven hundred twenty-one million, three hundred four thousand, six hundred forty-five".