509898991 has 16 divisors (see below), whose sum is σ = 614041600. Its totient is φ = 413628768.

The previous prime is 509898979. The next prime is 509898997. The reversal of 509898991 is 199898905.

It is a happy number.

It is not a de Polignac number, because 509898991 - 2¹¹ = 509896943 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 (509898997) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 236866 + ... + 239008.

It is an arithmetic number, because the mean of its divisors is an integer number (38377600).

Almost surely, 2^509898991 is an apocalyptic number.

509898991 is a deficient number, since it is larger than the sum of its proper divisors (104142609).

509898991 is a wasteful number, since it uses less digits than its factorization.

509898991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3958.

The product of its (nonzero) digits is 2099520, while the sum is 58.

The square root of 509898991 is about 22580.9430936797. The cubic root of 509898991 is about 798.9042242588.

The spelling of 509898991 in words is "five hundred nine million, eight hundred ninety-eight thousand, nine hundred ninety-one".