521871839 has 4 divisors (see below), whose sum is σ = 522999456. Its totient is φ = 520744224.

The previous prime is 521871799. The next prime is 521871859. The reversal of 521871839 is 938178125.

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 521871839 - 2²⁰ = 520823263 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 521871839.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (521871859) 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, 563114 + ... + 564039.

It is an arithmetic number, because the mean of its divisors is an integer number (130749864).

Almost surely, 2^521871839 is an apocalyptic number.

521871839 is a deficient number, since it is larger than the sum of its proper divisors (1127617).

521871839 is a wasteful number, since it uses less digits than its factorization.

521871839 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1127616.

The product of its digits is 120960, while the sum is 44.

The square root of 521871839 is about 22844.5144181267. The cubic root of 521871839 is about 805.1088874479.

The spelling of 521871839 in words is "five hundred twenty-one million, eight hundred seventy-one thousand, eight hundred thirty-nine".