720732121 has 2 divisors, whose sum is σ = 720732122. Its totient is φ = 720732120.

The previous prime is 720732083. The next prime is 720732161. The reversal of 720732121 is 121237027.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 466776025 + 253956096 = 21605^2 + 15936^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-720732121 is a prime.

It is not a weakly prime, because it can be changed into another prime (720732161) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 360366060 + 360366061.

It is an arithmetic number, because the mean of its divisors is an integer number (360366061).

Almost surely, 2^720732121 is an apocalyptic number.

It is an amenable number.

720732121 is a deficient number, since it is larger than the sum of its proper divisors (1).

720732121 is an equidigital number, since it uses as much as digits as its factorization.

720732121 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1176, while the sum is 25.

The square root of 720732121 is about 26846.4545331409. The cubic root of 720732121 is about 896.5846362649.

Adding to 720732121 its reverse (121237027), we get a palindrome (841969148).

The spelling of 720732121 in words is "seven hundred twenty million, seven hundred thirty-two thousand, one hundred twenty-one".