509991899 has 2 divisors, whose sum is σ = 509991900. Its totient is φ = 509991898.

The previous prime is 509991887. The next prime is 509991913. The reversal of 509991899 is 998199905.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 509991899 - 2¹⁶ = 509926363 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (509991809) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 254995949 + 254995950.

It is an arithmetic number, because the mean of its divisors is an integer number (254995950).

Almost surely, 2^509991899 is an apocalyptic number.

509991899 is a deficient number, since it is larger than the sum of its proper divisors (1).

509991899 is an equidigital number, since it uses as much as digits as its factorization.

509991899 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2361960, while the sum is 59.

The square root of 509991899 is about 22583.0002214055. Note that the first 3 decimals coincide. The cubic root of 509991899 is about 798.9527437286.

The spelling of 509991899 in words is "five hundred nine million, nine hundred ninety-one thousand, eight hundred ninety-nine".