721288991 has 2 divisors, whose sum is σ = 721288992. Its totient is φ = 721288990.

The previous prime is 721288987. The next prime is 721288999. The reversal of 721288991 is 199882127.

It is a weak prime.

It is an emirp because it is prime and its reverse (199882127) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 721288991 - 2² = 721288987 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (721288999) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 360644495 + 360644496.

It is an arithmetic number, because the mean of its divisors is an integer number (360644496).

Almost surely, 2^721288991 is an apocalyptic number.

721288991 is a deficient number, since it is larger than the sum of its proper divisors (1).

721288991 is an equidigital number, since it uses as much as digits as its factorization.

721288991 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 145152, while the sum is 47.

The square root of 721288991 is about 26856.8239186989. The cubic root of 721288991 is about 896.8154906688.

The spelling of 721288991 in words is "seven hundred twenty-one million, two hundred eighty-eight thousand, nine hundred ninety-one".