521312431 has 4 divisors (see below), whose sum is σ = 522612864. Its totient is φ = 520012000.

The previous prime is 521312423. The next prime is 521312437. The reversal of 521312431 is 134213125.

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 521312431 - 2³ = 521312423 is a prime.

It is a super-2 number, since 2×521312431² = 543533301430259522, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (521312437) 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, 649615 + ... + 650416.

It is an arithmetic number, because the mean of its divisors is an integer number (130653216).

Almost surely, 2^521312431 is an apocalyptic number.

521312431 is a deficient number, since it is larger than the sum of its proper divisors (1300433).

521312431 is a wasteful number, since it uses less digits than its factorization.

521312431 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1300432.

The product of its digits is 720, while the sum is 22.

The square root of 521312431 is about 22832.2673206145. The cubic root of 521312431 is about 804.8211122121.

Adding to 521312431 its reverse (134213125), we get a palindrome (655525556).

The spelling of 521312431 in words is "five hundred twenty-one million, three hundred twelve thousand, four hundred thirty-one".