428408221 has 8 divisors (see below), whose sum is σ = 439145784. Its totient is φ = 417684480.

The previous prime is 428408191. The next prime is 428408293. The reversal of 428408221 is 122804824.

It can be written as a sum of positive squares in 4 ways, for example, as 2604996 + 425803225 = 1614^2 + 20635^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 428408221 - 2⁹ = 428407709 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 (428408821) 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 7 ways as a sum of consecutive naturals, for example, 90895 + ... + 95491.

It is an arithmetic number, because the mean of its divisors is an integer number (54893223).

Almost surely, 2^428408221 is an apocalyptic number.

428408221 is a gapful number since it is divisible by the number (41) formed by its first and last digit.

It is an amenable number.

428408221 is a deficient number, since it is larger than the sum of its proper divisors (10737563).

428408221 is a wasteful number, since it uses less digits than its factorization.

428408221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6911.

The product of its (nonzero) digits is 8192, while the sum is 31.

The square root of 428408221 is about 20698.0245675765. The cubic root of 428408221 is about 753.8517234760.

The spelling of 428408221 in words is "four hundred twenty-eight million, four hundred eight thousand, two hundred twenty-one".