720165601 has 4 divisors (see below), whose sum is σ = 721043604. Its totient is φ = 719287600.

The previous prime is 720165587. The next prime is 720165689. The reversal of 720165601 is 106561027.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 106561027 = 179 ⋅595313.

It can be written as a sum of positive squares in 2 ways, for example, as 295805601 + 424360000 = 17199^2 + 20600^2 .

It is a cyclic number.

It is not a de Polignac number, because 720165601 - 2¹⁷ = 720034529 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 720165601.

It is not an unprimeable number, because it can be changed into a prime (720165401) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 437770 + ... + 439411.

It is an arithmetic number, because the mean of its divisors is an integer number (180260901).

Almost surely, 2^720165601 is an apocalyptic number.

It is an amenable number.

720165601 is a deficient number, since it is larger than the sum of its proper divisors (878003).

720165601 is an equidigital number, since it uses as much as digits as its factorization.

720165601 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 878002.

The product of its (nonzero) digits is 2520, while the sum is 28.

The square root of 720165601 is about 26835.9013450266. The cubic root of 720165601 is about 896.3496593316.

The spelling of 720165601 in words is "seven hundred twenty million, one hundred sixty-five thousand, six hundred one".