520421709 has 4 divisors (see below), whose sum is σ = 693895616. Its totient is φ = 346947804.

The previous prime is 520421653. The next prime is 520421717. The reversal of 520421709 is 907124025.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 520421709 - 2²⁸ = 251986253 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 (520421749) 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, 86736949 + ... + 86736954.

It is an arithmetic number, because the mean of its divisors is an integer number (173473904).

Almost surely, 2^520421709 is an apocalyptic number.

It is an amenable number.

520421709 is a deficient number, since it is larger than the sum of its proper divisors (173473907).

520421709 is a wasteful number, since it uses less digits than its factorization.

520421709 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 173473906.

The product of its (nonzero) digits is 5040, while the sum is 30.

The square root of 520421709 is about 22812.7532095536. The cubic root of 520421709 is about 804.3624745494.

The spelling of 520421709 in words is "five hundred twenty million, four hundred twenty-one thousand, seven hundred nine".