721840193 has 2 divisors, whose sum is σ = 721840194. Its totient is φ = 721840192.

The previous prime is 721840181. The next prime is 721840253. The reversal of 721840193 is 391048127.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 543029809 + 178810384 = 23303^2 + 13372^2 .

It is a cyclic number.

It is not a de Polignac number, because 721840193 - 2⁶ = 721840129 is a prime.

It is a Sophie Germain prime.

It is a Chen prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (721840393) by changing a digit.

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 as a sum of consecutive naturals, namely, 360920096 + 360920097.

It is an arithmetic number, because the mean of its divisors is an integer number (360920097).

Almost surely, 2^721840193 is an apocalyptic number.

It is an amenable number.

721840193 is a deficient number, since it is larger than the sum of its proper divisors (1).

721840193 is an equidigital number, since it uses as much as digits as its factorization.

721840193 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 12096, while the sum is 35.

The square root of 721840193 is about 26867.0838201692. The cubic root of 721840193 is about 897.0438783802.

The spelling of 721840193 in words is "seven hundred twenty-one million, eight hundred forty thousand, one hundred ninety-three".