720732161 has 2 divisors, whose sum is σ = 720732162. Its totient is φ = 720732160.

The previous prime is 720732121. The next prime is 720732167. The reversal of 720732161 is 161237027.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 381030400 + 339701761 = 19520^2 + 18431^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-720732161 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (720732167) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 360366080 + 360366081.

It is an arithmetic number, because the mean of its divisors is an integer number (360366081).

It is a Proth number, since it is equal to 21995 ⋅ 2¹⁵ + 1 and 21995 < 2¹⁵.

Almost surely, 2^720732161 is an apocalyptic number.

It is an amenable number.

720732161 is a deficient number, since it is larger than the sum of its proper divisors (1).

720732161 is an equidigital number, since it uses as much as digits as its factorization.

720732161 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 3528, while the sum is 29.

The square root of 720732161 is about 26846.4552781182. The cubic root of 720732161 is about 896.5846528515.

Adding to 720732161 its reverse (161237027), we get a palindrome (881969188).

The spelling of 720732161 in words is "seven hundred twenty million, seven hundred thirty-two thousand, one hundred sixty-one".