723639 has 16 divisors (see below), whose sum is σ = 1168128. Its totient is φ = 388992.

The previous prime is 723623. The next prime is 723661. The reversal of 723639 is 936327.

It is a happy number.

It is not a de Polignac number, because 723639 - 2⁴ = 723623 is a prime.

It is an Ulam number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (723439) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 657 + ... + 1370.

It is an arithmetic number, because the mean of its divisors is an integer number (73008).

2⁷²³⁶³⁹ is an apocalyptic number.

723639 is a deficient number, since it is larger than the sum of its proper divisors (444489).

723639 is a wasteful number, since it uses less digits than its factorization.

723639 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2054.

The product of its digits is 6804, while the sum is 30.

The square root of 723639 is about 850.6697361491. The cubic root of 723639 is about 89.7788396959.

The spelling of 723639 in words is "seven hundred twenty-three thousand, six hundred thirty-nine".