865723009 has 4 divisors (see below), whose sum is σ = 866582020. Its totient is φ = 864864000.

The previous prime is 865722961. The next prime is 865723021. The reversal of 865723009 is 900327568.

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

It can be written as a sum of positive squares in 2 ways, for example, as 619860609 + 245862400 = 24897^2 + 15680^2 .

It is a cyclic number.

It is not a de Polignac number, because 865723009 - 2⁹ = 865722497 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (865723069) 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, 427992 + ... + 430009.

It is an arithmetic number, because the mean of its divisors is an integer number (216645505).

Almost surely, 2^865723009 is an apocalyptic number.

It is an amenable number.

865723009 is a deficient number, since it is larger than the sum of its proper divisors (859011).

865723009 is a wasteful number, since it uses less digits than its factorization.

865723009 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 859010.

The product of its (nonzero) digits is 90720, while the sum is 40.

The square root of 865723009 is about 29423.1712940669. The cubic root of 865723009 is about 953.0733372395.

The spelling of 865723009 in words is "eight hundred sixty-five million, seven hundred twenty-three thousand, nine".