721197289 has 2 divisors, whose sum is σ = 721197290. Its totient is φ = 721197288.

The previous prime is 721197287. The next prime is 721197311. The reversal of 721197289 is 982791127.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 694849600 + 26347689 = 26360^2 + 5133^2 .

It is a cyclic number.

It is not a de Polignac number, because 721197289 - 2¹ = 721197287 is a prime.

Together with 721197287, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (721197287) 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 as a sum of consecutive naturals, namely, 360598644 + 360598645.

It is an arithmetic number, because the mean of its divisors is an integer number (360598645).

Almost surely, 2^721197289 is an apocalyptic number.

It is an amenable number.

721197289 is a deficient number, since it is larger than the sum of its proper divisors (1).

721197289 is an equidigital number, since it uses as much as digits as its factorization.

721197289 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 127008, while the sum is 46.

The square root of 721197289 is about 26855.1166260733. The cubic root of 721197289 is about 896.7774831293. Note that the first 3 decimals are identical.

The spelling of 721197289 in words is "seven hundred twenty-one million, one hundred ninety-seven thousand, two hundred eighty-nine".