721747417 has 2 divisors, whose sum is σ = 721747418. Its totient is φ = 721747416.

The previous prime is 721747387. The next prime is 721747441. The reversal of 721747417 is 714747127.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 721244736 + 502681 = 26856^2 + 709^2 .

It is an emirp because it is prime and its reverse (714747127) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 721747417 - 2⁷ = 721747289 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 721747417.

It is not a weakly prime, because it can be changed into another prime (721747457) 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, 360873708 + 360873709.

It is an arithmetic number, because the mean of its divisors is an integer number (360873709).

Almost surely, 2^721747417 is an apocalyptic number.

It is an amenable number.

721747417 is a deficient number, since it is larger than the sum of its proper divisors (1).

721747417 is an equidigital number, since it uses as much as digits as its factorization.

721747417 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 76832, while the sum is 40.

The square root of 721747417 is about 26865.3571909997. The cubic root of 721747417 is about 897.0054452619.

The spelling of 721747417 in words is "seven hundred twenty-one million, seven hundred forty-seven thousand, four hundred seventeen".