521663009 has 8 divisors (see below), whose sum is σ = 615418368. Its totient is φ = 432715680.

The previous prime is 521662987. The next prime is 521663029. The reversal of 521663009 is 900366125.

It is a happy number.

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 521663009 - 2²⁸ = 253227553 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (521663029) 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, 1201772 + ... + 1202205.

It is an arithmetic number, because the mean of its divisors is an integer number (76927296).

Almost surely, 2^521663009 is an apocalyptic number.

It is an amenable number.

521663009 is a deficient number, since it is larger than the sum of its proper divisors (93755359).

521663009 is a wasteful number, since it uses less digits than its factorization.

521663009 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2404015.

The product of its (nonzero) digits is 9720, while the sum is 32.

The square root of 521663009 is about 22839.9432792641. The cubic root of 521663009 is about 805.0014834791.

The spelling of 521663009 in words is "five hundred twenty-one million, six hundred sixty-three thousand, nine".