523661 has 4 divisors (see below), whose sum is σ = 537852. Its totient is φ = 509472.

The previous prime is 523657. The next prime is 523667. The reversal of 523661 is 166325.

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

It can be written as a sum of positive squares in 2 ways, for example, as 348100 + 175561 = 590^2 + 419^2 .

It is a cyclic number.

It is not a de Polignac number, because 523661 - 2² = 523657 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 523661.

It is not an unprimeable number, because it can be changed into a prime (523667) 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, 7040 + ... + 7113.

It is an arithmetic number, because the mean of its divisors is an integer number (134463).

2⁵²³⁶⁶¹ is an apocalyptic number.

It is an amenable number.

523661 is a deficient number, since it is larger than the sum of its proper divisors (14191).

523661 is a wasteful number, since it uses less digits than its factorization.

523661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14190.

The product of its digits is 1080, while the sum is 23.

The square root of 523661 is about 723.6442496144. The cubic root of 523661 is about 80.6027903891.

Adding to 523661 its reverse (166325), we get a palindrome (689986).

The spelling of 523661 in words is "five hundred twenty-three thousand, six hundred sixty-one".