720400161 has 16 divisors (see below), whose sum is σ = 1056432384. Its totient is φ = 433889664.

The previous prime is 720400159. The next prime is 720400183. The reversal of 720400161 is 161004027.

720400161 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 720400161 - 2¹ = 720400159 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (720400111) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 194676 + ... + 198341.

It is an arithmetic number, because the mean of its divisors is an integer number (66027024).

Almost surely, 2^720400161 is an apocalyptic number.

It is an amenable number.

720400161 is a deficient number, since it is larger than the sum of its proper divisors (336032223).

720400161 is a wasteful number, since it uses less digits than its factorization.

720400161 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 393080.

The product of its (nonzero) digits is 336, while the sum is 21.

The square root of 720400161 is about 26840.2712542180. The cubic root of 720400161 is about 896.4469633192.

Adding to 720400161 its reverse (161004027), we get a palindrome (881404188).

The spelling of 720400161 in words is "seven hundred twenty million, four hundred thousand, one hundred sixty-one".