721675609 has 2 divisors, whose sum is σ = 721675610. Its totient is φ = 721675608.

The previous prime is 721675597. The next prime is 721675627. The reversal of 721675609 is 906576127.

721675609 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 624850009 + 96825600 = 24997^2 + 9840^2 .

It is a cyclic number.

It is not a de Polignac number, because 721675609 - 2¹³ = 721667417 is a prime.

It is not a weakly prime, because it can be changed into another prime (721675709) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 360837804 + 360837805.

It is an arithmetic number, because the mean of its divisors is an integer number (360837805).

Almost surely, 2^721675609 is an apocalyptic number.

It is an amenable number.

721675609 is a deficient number, since it is larger than the sum of its proper divisors (1).

721675609 is an equidigital number, since it uses as much as digits as its factorization.

721675609 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 158760, while the sum is 43.

The square root of 721675609 is about 26864.0207154476. The cubic root of 721675609 is about 896.9756960256.

The spelling of 721675609 in words is "seven hundred twenty-one million, six hundred seventy-five thousand, six hundred nine".