509898989 has 8 divisors (see below), whose sum is σ = 513673752. Its totient is φ = 506134080.

The previous prime is 509898979. The next prime is 509898997. The reversal of 509898989 is 989898905.

It can be written as a sum of positive squares in 4 ways, for example, as 202492900 + 307406089 = 14230^2 + 17533^2 .

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 509898989 - 2⁴ = 509898973 is a prime.

It is an alternating number because its digits alternate between odd and even.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (509898979) 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, 124799 + ... + 128819.

It is an arithmetic number, because the mean of its divisors is an integer number (64209219).

Almost surely, 2^509898989 is an apocalyptic number.

It is an amenable number.

509898989 is a deficient number, since it is larger than the sum of its proper divisors (3774763).

509898989 is a wasteful number, since it uses less digits than its factorization.

509898989 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4927.

The product of its (nonzero) digits is 16796160, while the sum is 65.

The square root of 509898989 is about 22580.9430493945. The cubic root of 509898989 is about 798.9042232143.

The spelling of 509898989 in words is "five hundred nine million, eight hundred ninety-eight thousand, nine hundred eighty-nine".