723681 has 24 divisors (see below), whose sum is σ = 1249440. Its totient is φ = 412776.

The previous prime is 723661. The next prime is 723721. The reversal of 723681 is 186327.

It is not a de Polignac number, because 723681 - 2⁶ = 723617 is a prime.

It is a super-2 number, since 2×723681² = 1047428379522, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 723681.

It is not an unprimeable number, because it can be changed into a prime (723601) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1050 + ... + 1596.

It is an arithmetic number, because the mean of its divisors is an integer number (52060).

2⁷²³⁶⁸¹ is an apocalyptic number.

It is an amenable number.

723681 is a deficient number, since it is larger than the sum of its proper divisors (525759).

723681 is a wasteful number, since it uses less digits than its factorization.

723681 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 570 (or 557 counting only the distinct ones).

The product of its digits is 2016, while the sum is 27.

The square root of 723681 is about 850.6944222222. The cubic root of 723681 is about 89.7805765832.

The spelling of 723681 in words is "seven hundred twenty-three thousand, six hundred eighty-one".