720735731 has 2 divisors, whose sum is σ = 720735732. Its totient is φ = 720735730.

The previous prime is 720735703. The next prime is 720735733. The reversal of 720735731 is 137537027.

It is a strong prime.

It is an emirp because it is prime and its reverse (137537027) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 720735731 - 2⁶ = 720735667 is a prime.

It is a super-2 number, since 2×720735731² = 1038919987880208722, which contains 22 as substring.

Together with 720735733, it forms a pair of twin primes.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 720735691 and 720735700.

It is not a weakly prime, because it can be changed into another prime (720735733) 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, 360367865 + 360367866.

It is an arithmetic number, because the mean of its divisors is an integer number (360367866).

Almost surely, 2^720735731 is an apocalyptic number.

720735731 is a deficient number, since it is larger than the sum of its proper divisors (1).

720735731 is an equidigital number, since it uses as much as digits as its factorization.

720735731 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 30870, while the sum is 35.

The square root of 720735731 is about 26846.5217672607. The cubic root of 720735731 is about 896.5861331989.

The spelling of 720735731 in words is "seven hundred twenty million, seven hundred thirty-five thousand, seven hundred thirty-one".