520139999 has 4 divisors (see below), whose sum is σ = 520827864. Its totient is φ = 519452136.

The previous prime is 520139959. The next prime is 520140053. The reversal of 520139999 is 999931025.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 520139999 - 2²⁰ = 519091423 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 (520139909) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 342797 + ... + 344310.

It is an arithmetic number, because the mean of its divisors is an integer number (130206966).

Almost surely, 2^520139999 is an apocalyptic number.

520139999 is a deficient number, since it is larger than the sum of its proper divisors (687865).

520139999 is an equidigital number, since it uses as much as digits as its factorization.

520139999 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 687864.

The product of its (nonzero) digits is 196830, while the sum is 47.

The square root of 520139999 is about 22806.5779765400. The cubic root of 520139999 is about 804.2173115995.

The spelling of 520139999 in words is "five hundred twenty million, one hundred thirty-nine thousand, nine hundred ninety-nine".