421778 has 16 divisors (see below), whose sum is σ = 739584. Its totient is φ = 176640.

The previous prime is 421741. The next prime is 421783. The reversal of 421778 is 877124.

421778 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It is a self number, because there is not a number n which added to its sum of digits gives 421778.

It is an unprimeable number.

421778 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 338 + ... + 978.

It is an arithmetic number, because the mean of its divisors is an integer number (46224).

2⁴²¹⁷⁷⁸ is an apocalyptic number.

421778 is a deficient number, since it is larger than the sum of its proper divisors (317806).

421778 is a wasteful number, since it uses less digits than its factorization.

421778 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 697.

The product of its digits is 3136, while the sum is 29.

The square root of 421778 is about 649.4443779108. Note that the first 3 decimals coincide. The cubic root of 421778 is about 74.9942514112.

The spelling of 421778 in words is "four hundred twenty-one thousand, seven hundred seventy-eight".