509995987 has 4 divisors (see below), whose sum is σ = 510129720. Its totient is φ = 509862256.

The previous prime is 509995949. The next prime is 509995991. The reversal of 509995987 is 789599905.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 789599905 = 5 ⋅157919981.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-509995987 is a prime.

It is a super-2 number, since 2×509995987² = 520191813512208338, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (509995687) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 60973 + ... + 68830.

It is an arithmetic number, because the mean of its divisors is an integer number (127532430).

Almost surely, 2^509995987 is an apocalyptic number.

509995987 is a deficient number, since it is larger than the sum of its proper divisors (133733).

509995987 is a wasteful number, since it uses less digits than its factorization.

509995987 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 133732.

The product of its (nonzero) digits is 9185400, while the sum is 61.

The square root of 509995987 is about 22583.0907317843. The cubic root of 509995987 is about 798.9548784750.

The spelling of 509995987 in words is "five hundred nine million, nine hundred ninety-five thousand, nine hundred eighty-seven".