878765821 has 4 divisors (see below), whose sum is σ = 887297632. Its totient is φ = 870234012.

The previous prime is 878765779. The next prime is 878765831. The reversal of 878765821 is 128567878.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 878765821 - 2¹¹ = 878763773 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 (878765831) 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, 4265751 + ... + 4265956.

It is an arithmetic number, because the mean of its divisors is an integer number (221824408).

Almost surely, 2^878765821 is an apocalyptic number.

It is an amenable number.

878765821 is a deficient number, since it is larger than the sum of its proper divisors (8531811).

878765821 is a wasteful number, since it uses less digits than its factorization.

878765821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8531810.

The product of its digits is 1505280, while the sum is 52.

The square root of 878765821 is about 29643.9845668561. The cubic root of 878765821 is about 957.8357716835.

The spelling of 878765821 in words is "eight hundred seventy-eight million, seven hundred sixty-five thousand, eight hundred twenty-one".