721273591 has 2 divisors, whose sum is σ = 721273592. Its totient is φ = 721273590.

The previous prime is 721273589. The next prime is 721273639. The reversal of 721273591 is 195372127.

It is a weak prime.

It is an emirp because it is prime and its reverse (195372127) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 721273591 - 2¹ = 721273589 is a prime.

Together with 721273589, it forms a pair of twin primes.

It is a self number, because there is not a number n which added to its sum of digits gives 721273591.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (721273571) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 360636795 + 360636796.

It is an arithmetic number, because the mean of its divisors is an integer number (360636796).

Almost surely, 2^721273591 is an apocalyptic number.

721273591 is a deficient number, since it is larger than the sum of its proper divisors (1).

721273591 is an equidigital number, since it uses as much as digits as its factorization.

721273591 is an evil number, because the sum of its binary digits is even.

The product of its digits is 26460, while the sum is 37.

The square root of 721273591 is about 26856.5372116362. The cubic root of 721273591 is about 896.8091080876.

The spelling of 721273591 in words is "seven hundred twenty-one million, two hundred seventy-three thousand, five hundred ninety-one".