531123521 has 4 divisors (see below), whose sum is σ = 554215872. Its totient is φ = 508031172.

The previous prime is 531123491. The next prime is 531123529. The reversal of 531123521 is 125321135.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 531123521 - 2⁶ = 531123457 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (23), and also a Moran number because the ratio is a prime number: 23092327 = 531123521 / (5 + 3 + 1 + 1 + 2 + 3 + 5 + 2 + 1).

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (531123529) 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, 11546141 + ... + 11546186.

It is an arithmetic number, because the mean of its divisors is an integer number (138553968).

Almost surely, 2^531123521 is an apocalyptic number.

It is an amenable number.

531123521 is a deficient number, since it is larger than the sum of its proper divisors (23092351).

531123521 is a wasteful number, since it uses less digits than its factorization.

531123521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 23092350.

The product of its digits is 900, while the sum is 23.

The square root of 531123521 is about 23046.1172651707. The cubic root of 531123521 is about 809.8386718280.

Adding to 531123521 its reverse (125321135), we get a palindrome (656444656).

The spelling of 531123521 in words is "five hundred thirty-one million, one hundred twenty-three thousand, five hundred twenty-one".