723661 has 2 divisors, whose sum is σ = 723662. Its totient is φ = 723660.

The previous prime is 723623. The next prime is 723721. The reversal of 723661 is 166327.

723661 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 670761 + 52900 = 819^2 + 230^2 .

It is a cyclic number.

It is not a de Polignac number, because 723661 - 2¹¹ = 721613 is a prime.

723661 is a lucky number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (723601) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 361830 + 361831.

It is an arithmetic number, because the mean of its divisors is an integer number (361831).

2⁷²³⁶⁶¹ is an apocalyptic number.

It is an amenable number.

723661 is a deficient number, since it is larger than the sum of its proper divisors (1).

723661 is an equidigital number, since it uses as much as digits as its factorization.

723661 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1512, while the sum is 25.

The square root of 723661 is about 850.6826670387. The cubic root of 723661 is about 89.7797495024.

Adding to 723661 its reverse (166327), we get a palindrome (889988).

The spelling of 723661 in words is "seven hundred twenty-three thousand, six hundred sixty-one".