520613221 has 4 divisors (see below), whose sum is σ = 522255852. Its totient is φ = 518970592.

The previous prime is 520613209. The next prime is 520613263. The reversal of 520613221 is 122316025.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 73290721 + 447322500 = 8561^2 + 21150^2 .

It is a cyclic number.

It is not a de Polignac number, because 520613221 - 2⁵ = 520613189 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 520613192 and 520613201.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (520613521) 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, 820840 + ... + 821473.

It is an arithmetic number, because the mean of its divisors is an integer number (130563963).

Almost surely, 2^520613221 is an apocalyptic number.

It is an amenable number.

520613221 is a deficient number, since it is larger than the sum of its proper divisors (1642631).

520613221 is a wasteful number, since it uses less digits than its factorization.

520613221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1642630.

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

The square root of 520613221 is about 22816.9503001606. The cubic root of 520613221 is about 804.4611292696.

Adding to 520613221 its reverse (122316025), we get a palindrome (642929246).

The spelling of 520613221 in words is "five hundred twenty million, six hundred thirteen thousand, two hundred twenty-one".