428308821 has 12 divisors (see below), whose sum is σ = 621396672. Its totient is φ = 284279976.

The previous prime is 428308817. The next prime is 428308843. The reversal of 428308821 is 128803824.

It is a happy number.

It is not a de Polignac number, because 428308821 - 2² = 428308817 is a prime.

It is a super-2 number, since 2×428308821² = 366896892292820082, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (428308861) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 102781 + ... + 106866.

It is an arithmetic number, because the mean of its divisors is an integer number (51783056).

Almost surely, 2^428308821 is an apocalyptic number.

It is an amenable number.

428308821 is a deficient number, since it is larger than the sum of its proper divisors (193087851).

428308821 is a wasteful number, since it uses less digits than its factorization.

428308821 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 209880 (or 209877 counting only the distinct ones).

The product of its (nonzero) digits is 24576, while the sum is 36.

The square root of 428308821 is about 20695.6232329447. The cubic root of 428308821 is about 753.7934156489.

The spelling of 428308821 in words is "four hundred twenty-eight million, three hundred eight thousand, eight hundred twenty-one".