819520643959 has 4 divisors (see below), whose sum is σ = 819547679304. Its totient is φ = 819493608616.

The previous prime is 819520643957. The next prime is 819520644029. The reversal of 819520643959 is 959346025918.

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 819520643959 - 2¹ = 819520643957 is a prime.

It is a super-2 number, since 2×819520643959² (a number of 25 digits) contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 819520643897 and 819520643906.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (819520643957) 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, 13472152 + ... + 13532845.

It is an arithmetic number, because the mean of its divisors is an integer number (204886919826).

Almost surely, 2^819520643959 is an apocalyptic number.

819520643959 is a deficient number, since it is larger than the sum of its proper divisors (27035345).

819520643959 is a wasteful number, since it uses less digits than its factorization.

819520643959 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 27035344.

The product of its (nonzero) digits is 20995200, while the sum is 61.

The spelling of 819520643959 in words is "eight hundred nineteen billion, five hundred twenty million, six hundred forty-three thousand, nine hundred fifty-nine".