720613261 has 2 divisors, whose sum is σ = 720613262. Its totient is φ = 720613260.

The previous prime is 720613249. The next prime is 720613277. The reversal of 720613261 is 162316027.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 619711236 + 100902025 = 24894^2 + 10045^2 .

It is an emirp because it is prime and its reverse (162316027) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 720613261 - 2⁹ = 720612749 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (720613241) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 360306630 + 360306631.

It is an arithmetic number, because the mean of its divisors is an integer number (360306631).

Almost surely, 2^720613261 is an apocalyptic number.

It is an amenable number.

720613261 is a deficient number, since it is larger than the sum of its proper divisors (1).

720613261 is an equidigital number, since it uses as much as digits as its factorization.

720613261 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 3024, while the sum is 28.

The square root of 720613261 is about 26844.2407417308. The cubic root of 720613261 is about 896.5353466118.

Adding to 720613261 its reverse (162316027), we get a palindrome (882929288).

The spelling of 720613261 in words is "seven hundred twenty million, six hundred thirteen thousand, two hundred sixty-one".