720913 has 2 divisors, whose sum is σ = 720914. Its totient is φ = 720912.

The previous prime is 720901. The next prime is 720931. The reversal of 720913 is 319027.

Together with next prime (720931) it forms an Ormiston pair, because they use the same digits, order apart.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 399424 + 321489 = 632^2 + 567^2 .

It is an emirp because it is prime and its reverse (319027) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-720913 is a prime.

720913 is a lucky number.

It is not a weakly prime, because it can be changed into another prime (720943) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (5) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 360456 + 360457.

It is an arithmetic number, because the mean of its divisors is an integer number (360457).

2⁷²⁰⁹¹³ is an apocalyptic number.

It is an amenable number.

720913 is a deficient number, since it is larger than the sum of its proper divisors (1).

720913 is an equidigital number, since it uses as much as digits as its factorization.

720913 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 378, while the sum is 22.

The square root of 720913 is about 849.0659573908. The cubic root of 720913 is about 89.6659633971.

The spelling of 720913 in words is "seven hundred twenty thousand, nine hundred thirteen".