521623 has 4 divisors (see below), whose sum is σ = 539640. Its totient is φ = 503608.

The previous prime is 521603. The next prime is 521641. The reversal of 521623 is 326125.

It is a happy number.

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 521623 - 2¹³ = 513431 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 521623.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (521603) 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, 8965 + ... + 9022.

It is an arithmetic number, because the mean of its divisors is an integer number (134910).

2⁵²¹⁶²³ is an apocalyptic number.

521623 is a deficient number, since it is larger than the sum of its proper divisors (18017).

521623 is a wasteful number, since it uses less digits than its factorization.

521623 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18016.

The product of its digits is 360, while the sum is 19.

The square root of 521623 is about 722.2347263875. The cubic root of 521623 is about 80.4980903061.

Adding to 521623 its reverse (326125), we get a palindrome (847748).

The spelling of 521623 in words is "five hundred twenty-one thousand, six hundred twenty-three".