720161 has 8 divisors (see below), whose sum is σ = 801024. Its totient is φ = 642960.

The previous prime is 720151. The next prime is 720173. The reversal of 720161 is 161027.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-720161 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (720101) 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 in 7 ways as a sum of consecutive naturals, for example, 491 + ... + 1296.

It is an arithmetic number, because the mean of its divisors is an integer number (100128).

2⁷²⁰¹⁶¹ is an apocalyptic number.

It is an amenable number.

720161 is a deficient number, since it is larger than the sum of its proper divisors (80863).

720161 is a wasteful number, since it uses less digits than its factorization.

720161 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1831.

The product of its (nonzero) digits is 84, while the sum is 17.

The square root of 720161 is about 848.6230022808. The cubic root of 720161 is about 89.6347750459.

Adding to 720161 its reverse (161027), we get a palindrome (881188).

The spelling of 720161 in words is "seven hundred twenty thousand, one hundred sixty-one".