720919 has 4 divisors (see below), whose sum is σ = 763344. Its totient is φ = 678496.

The previous prime is 720913. The next prime is 720931. The reversal of 720919 is 919027.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 919027 = 457 ⋅2011.

It is a cyclic number.

It is not a de Polignac number, because 720919 - 2⁵ = 720887 is a prime.

It is a super-2 number, since 2×720919² = 1039448409122, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (720913) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 21187 + ... + 21220.

It is an arithmetic number, because the mean of its divisors is an integer number (190836).

2⁷²⁰⁹¹⁹ is an apocalyptic number.

720919 is a deficient number, since it is larger than the sum of its proper divisors (42425).

720919 is a wasteful number, since it uses less digits than its factorization.

720919 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 42424.

The product of its (nonzero) digits is 1134, while the sum is 28.

The square root of 720919 is about 849.0694906779. The cubic root of 720919 is about 89.6662121531. Note that the first 3 decimals are identical.

The spelling of 720919 in words is "seven hundred twenty thousand, nine hundred nineteen".