520398661 has 4 divisors (see below), whose sum is σ = 520568524. Its totient is φ = 520228800.

The previous prime is 520398653. The next prime is 520398701. The reversal of 520398661 is 166893025.

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 118396161 + 402002500 = 10881^2 + 20050^2 .

It is a cyclic number.

It is not a de Polignac number, because 520398661 - 2³ = 520398653 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (520398631) 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, 80250 + ... + 86491.

It is an arithmetic number, because the mean of its divisors is an integer number (130142131).

Almost surely, 2^520398661 is an apocalyptic number.

It is an amenable number.

520398661 is a deficient number, since it is larger than the sum of its proper divisors (169863).

520398661 is a wasteful number, since it uses less digits than its factorization.

520398661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 169862.

The product of its (nonzero) digits is 77760, while the sum is 40.

The square root of 520398661 is about 22812.2480479237. The cubic root of 520398661 is about 804.3506000640.

The spelling of 520398661 in words is "five hundred twenty million, three hundred ninety-eight thousand, six hundred sixty-one".