720671809 has 16 divisors (see below), whose sum is σ = 851586624. Its totient is φ = 601243200.

The previous prime is 720671789. The next prime is 720671827. The reversal of 720671809 is 908176027.

It is a cyclic number.

It is not a de Polignac number, because 720671809 - 2¹⁵ = 720639041 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (720671869) 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 15 ways as a sum of consecutive naturals, for example, 10174 + ... + 39304.

It is an arithmetic number, because the mean of its divisors is an integer number (53224164).

Almost surely, 2^720671809 is an apocalyptic number.

It is an amenable number.

720671809 is a deficient number, since it is larger than the sum of its proper divisors (130914815).

720671809 is a wasteful number, since it uses less digits than its factorization.

720671809 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 29328.

The product of its (nonzero) digits is 42336, while the sum is 40.

The square root of 720671809 is about 26845.3312328233. The cubic root of 720671809 is about 896.5596263620.

The spelling of 720671809 in words is "seven hundred twenty million, six hundred seventy-one thousand, eight hundred nine".