720139 has 4 divisors (see below), whose sum is σ = 823024. Its totient is φ = 617256.

The previous prime is 720133. The next prime is 720151. The reversal of 720139 is 931027.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 931027 = 521 ⋅1787.

It is a cyclic number.

It is not a de Polignac number, because 720139 - 2¹³ = 711947 is a prime.

It is a Duffinian number.

720139 is a lucky number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 720139.

It is not an unprimeable number, because it can be changed into a prime (720133) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 51432 + ... + 51445.

It is an arithmetic number, because the mean of its divisors is an integer number (205756).

2⁷²⁰¹³⁹ is an apocalyptic number.

720139 is a deficient number, since it is larger than the sum of its proper divisors (102885).

720139 is a wasteful number, since it uses less digits than its factorization.

720139 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 102884.

The product of its (nonzero) digits is 378, while the sum is 22.

The square root of 720139 is about 848.6100400066. The cubic root of 720139 is about 89.6338622939.

The spelling of 720139 in words is "seven hundred twenty thousand, one hundred thirty-nine".