423878821 has 4 divisors (see below), whose sum is σ = 433736512. Its totient is φ = 414021132.

The previous prime is 423878803. The next prime is 423878831. The reversal of 423878821 is 128878324.

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 423878821 - 2⁹ = 423878309 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (43), and also a Moran number because the ratio is a prime number: 9857647 = 423878821 / (4 + 2 + 3 + 8 + 7 + 8 + 8 + 2 + 1).

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (423878831) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4928781 + ... + 4928866.

It is an arithmetic number, because the mean of its divisors is an integer number (108434128).

Almost surely, 2^423878821 is an apocalyptic number.

It is an amenable number.

423878821 is a deficient number, since it is larger than the sum of its proper divisors (9857691).

423878821 is an equidigital number, since it uses as much as digits as its factorization.

423878821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9857690.

The product of its digits is 172032, while the sum is 43.

The square root of 423878821 is about 20588.3175854658. The cubic root of 423878821 is about 751.1855743785.

The spelling of 423878821 in words is "four hundred twenty-three million, eight hundred seventy-eight thousand, eight hundred twenty-one".