720155 has 4 divisors (see below), whose sum is σ = 864192. Its totient is φ = 576120.

The previous prime is 720151. The next prime is 720173. The reversal of 720155 is 551027.

It is a semiprime because it is the product of two primes.

It is not a de Polignac number, because 720155 - 2² = 720151 is a prime.

It is an Ulam number.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (720151) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 72011 + ... + 72020.

It is an arithmetic number, because the mean of its divisors is an integer number (216048).

2⁷²⁰¹⁵⁵ is an apocalyptic number.

720155 is a deficient number, since it is larger than the sum of its proper divisors (144037).

720155 is a wasteful number, since it uses less digits than its factorization.

720155 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 144036.

The product of its (nonzero) digits is 350, while the sum is 20.

The square root of 720155 is about 848.6194671347. The cubic root of 720155 is about 89.6345261154.

The spelling of 720155 in words is "seven hundred twenty thousand, one hundred fifty-five".