721296647 has 2 divisors, whose sum is σ = 721296648. Its totient is φ = 721296646.

The previous prime is 721296571. The next prime is 721296707. The reversal of 721296647 is 746692127.

It is a strong prime.

It is an emirp because it is prime and its reverse (746692127) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 721296647 - 2¹⁰ = 721295623 is a prime.

It is equal to p_37297745 and since 721296647 and 37297745 have the same sum of digits, it is a Honaker prime.

It is a junction number, because it is equal to n+sod(n) for n = 721296598 and 721296607.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (721296047) 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, 360648323 + 360648324.

It is an arithmetic number, because the mean of its divisors is an integer number (360648324).

Almost surely, 2^721296647 is an apocalyptic number.

721296647 is a deficient number, since it is larger than the sum of its proper divisors (1).

721296647 is an equidigital number, since it uses as much as digits as its factorization.

721296647 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 254016, while the sum is 44.

The square root of 721296647 is about 26856.9664519283. The cubic root of 721296647 is about 896.8186636897.

The spelling of 721296647 in words is "seven hundred twenty-one million, two hundred ninety-six thousand, six hundred forty-seven".