521531243 has 4 divisors (see below), whose sum is σ = 535626720. Its totient is φ = 507435768.

The previous prime is 521531239. The next prime is 521531249. The reversal of 521531243 is 342135125.

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 521531243 - 2² = 521531239 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (521531249) 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, 7047683 + ... + 7047756.

It is an arithmetic number, because the mean of its divisors is an integer number (133906680).

Almost surely, 2^521531243 is an apocalyptic number.

521531243 is a deficient number, since it is larger than the sum of its proper divisors (14095477).

521531243 is a wasteful number, since it uses less digits than its factorization.

521531243 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14095476.

The product of its digits is 3600, while the sum is 26.

The square root of 521531243 is about 22837.0585452680. The cubic root of 521531243 is about 804.9336997722.

Adding to 521531243 its reverse (342135125), we get a palindrome (863666368).

The spelling of 521531243 in words is "five hundred twenty-one million, five hundred thirty-one thousand, two hundred forty-three".