521638673 has 8 divisors (see below), whose sum is σ = 549410400. Its totient is φ = 493898688.

The previous prime is 521638651. The next prime is 521638687. The reversal of 521638673 is 376836125.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 521638673 - 2²⁰ = 520590097 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 521638673.

It is not an unprimeable number, because it can be changed into a prime (521638603) 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, 30665 + ... + 44537.

It is an arithmetic number, because the mean of its divisors is an integer number (68676300).

Almost surely, 2^521638673 is an apocalyptic number.

It is an amenable number.

521638673 is a deficient number, since it is larger than the sum of its proper divisors (27771727).

521638673 is a wasteful number, since it uses less digits than its factorization.

521638673 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15871.

The product of its digits is 181440, while the sum is 41.

The square root of 521638673 is about 22839.4105221654. The cubic root of 521638673 is about 804.9889652950.

The spelling of 521638673 in words is "five hundred twenty-one million, six hundred thirty-eight thousand, six hundred seventy-three".