428640 has 96 divisors (see below), whose sum is σ = 1451520. Its totient is φ = 105984.

The previous prime is 428639. The next prime is 428657. The reversal of 428640 is 46824.

It is a tau number, because it is divible by the number of its divisors (96).

It is a Harshad number since it is a multiple of its sum of digits (24).

It is a self number, because there is not a number n which added to its sum of digits gives 428640.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 9097 + ... + 9143.

It is an arithmetic number, because the mean of its divisors is an integer number (15120).

2⁴²⁸⁶⁴⁰ is an apocalyptic number.

428640 is a gapful number since it is divisible by the number (40) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 428640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (725760).

428640 is an abundant number, since it is smaller than the sum of its proper divisors (1022880).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

428640 is a wasteful number, since it uses less digits than its factorization.

428640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 84 (or 76 counting only the distinct ones).

The product of its (nonzero) digits is 1536, while the sum is 24.

The square root of 428640 is about 654.7060409069. The cubic root of 428640 is about 75.3987649515.

The spelling of 428640 in words is "four hundred twenty-eight thousand, six hundred forty".