521205431 has 8 divisors (see below), whose sum is σ = 553779360. Its totient is φ = 490541664.

The previous prime is 521205401. The next prime is 521205439. The reversal of 521205431 is 134502125.

It is a de Polignac number, because none of the positive numbers 2^k-521205431 is a prime.

It is a super-2 number, since 2×521205431² = 543310202607791522, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 521205397 and 521205406.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (521205439) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 48131 + ... + 57956.

It is an arithmetic number, because the mean of its divisors is an integer number (69222420).

Almost surely, 2^521205431 is an apocalyptic number.

521205431 is a deficient number, since it is larger than the sum of its proper divisors (32573929).

521205431 is an equidigital number, since it uses as much as digits as its factorization.

521205431 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 106138 (or 106104 counting only the distinct ones).

The product of its (nonzero) digits is 1200, while the sum is 23.

The square root of 521205431 is about 22829.9240252788. The cubic root of 521205431 is about 804.7660449457.

Adding to 521205431 its reverse (134502125), we get a palindrome (655707556).

The spelling of 521205431 in words is "five hundred twenty-one million, two hundred five thousand, four hundred thirty-one".