819878461 has 4 divisors (see below), whose sum is σ = 820189692. Its totient is φ = 819567232.

The previous prime is 819878453. The next prime is 819878471. The reversal of 819878461 is 164878918.

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: 164878918 = 2 ⋅82439459.

It can be written as a sum of positive squares in 2 ways, for example, as 356983236 + 462895225 = 18894^2 + 21515^2 .

It is a cyclic number.

It is not a de Polignac number, because 819878461 - 2³ = 819878453 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 819878399 and 819878408.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (819878471) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 151630 + ... + 156943.

It is an arithmetic number, because the mean of its divisors is an integer number (205047423).

Almost surely, 2^819878461 is an apocalyptic number.

It is an amenable number.

819878461 is a deficient number, since it is larger than the sum of its proper divisors (311231).

819878461 is a wasteful number, since it uses less digits than its factorization.

819878461 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 311230.

The product of its digits is 774144, while the sum is 52.

The square root of 819878461 is about 28633.5198849181. The cubic root of 819878461 is about 935.9439164079.

The spelling of 819878461 in words is "eight hundred nineteen million, eight hundred seventy-eight thousand, four hundred sixty-one".