723561 has 16 divisors (see below), whose sum is σ = 1013760. Its totient is φ = 458640.

The previous prime is 723559. The next prime is 723563. The reversal of 723561 is 165327.

It is an interprime number because it is at equal distance from previous prime (723559) and next prime (723563).

It is not a de Polignac number, because 723561 - 2¹ = 723559 is a prime.

It is a Curzon number.

723561 is a lucky number.

It is not an unprimeable number, because it can be changed into a prime (723563) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 9120 + ... + 9198.

It is an arithmetic number, because the mean of its divisors is an integer number (63360).

2⁷²³⁵⁶¹ is an apocalyptic number.

723561 is a gapful number since it is divisible by the number (71) formed by its first and last digit.

It is an amenable number.

723561 is a deficient number, since it is larger than the sum of its proper divisors (290199).

723561 is a wasteful number, since it uses less digits than its factorization.

723561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 196.

The product of its digits is 1260, while the sum is 24.

The square root of 723561 is about 850.6238886841. The cubic root of 723561 is about 89.7756138696.

Adding to 723561 its reverse (165327), we get a palindrome (888888).

The spelling of 723561 in words is "seven hundred twenty-three thousand, five hundred sixty-one".