723666509 has 4 divisors (see below), whose sum is σ = 761754240. Its totient is φ = 685578780.

The previous prime is 723666499. The next prime is 723666521. The reversal of 723666509 is 905666327.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 905666327 = 197 ⋅4597291.

It is a cyclic number.

It is not a de Polignac number, because 723666509 - 2⁸ = 723666253 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 723666509.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (723666529) 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, 19043837 + ... + 19043874.

It is an arithmetic number, because the mean of its divisors is an integer number (190438560).

Almost surely, 2^723666509 is an apocalyptic number.

It is an amenable number.

723666509 is a deficient number, since it is larger than the sum of its proper divisors (38087731).

723666509 is a wasteful number, since it uses less digits than its factorization.

723666509 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 38087730.

The product of its (nonzero) digits is 408240, while the sum is 44.

The square root of 723666509 is about 26901.0503326543. The cubic root of 723666509 is about 897.7997732334.

The spelling of 723666509 in words is "seven hundred twenty-three million, six hundred sixty-six thousand, five hundred nine".