661723 has 4 divisors (see below), whose sum is σ = 665280. Its totient is φ = 658168.

The previous prime is 661721. The next prime is 661741. The reversal of 661723 is 327166.

661723 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 661723 - 2¹ = 661721 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (661721) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1483 + ... + 1876.

It is an arithmetic number, because the mean of its divisors is an integer number (166320).

2⁶⁶¹⁷²³ is an apocalyptic number.

661723 is a deficient number, since it is larger than the sum of its proper divisors (3557).

661723 is a wasteful number, since it uses less digits than its factorization.

661723 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3556.

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

The square root of 661723 is about 813.4635824670. The cubic root of 661723 is about 87.1415759784.

Adding to 661723 its reverse (327166), we get a palindrome (988889).

The spelling of 661723 in words is "six hundred sixty-one thousand, seven hundred twenty-three".