840428 has 12 divisors (see below), whose sum is σ = 1480920. Its totient is φ = 417312.

The previous prime is 840353. The next prime is 840439. The reversal of 840428 is 824048.

It is an Ulam number.

It is a junction number, because it is equal to n+sod(n) for n = 840397 and 840406.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 840428.

It is an unprimeable 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 3 ways as a sum of consecutive naturals, for example, 8 + ... + 1296.

It is an arithmetic number, because the mean of its divisors is an integer number (123410).

2⁸⁴⁰⁴²⁸ is an apocalyptic number.

It is an amenable number.

840428 is a deficient number, since it is larger than the sum of its proper divisors (640492).

840428 is a wasteful number, since it uses less digits than its factorization.

840428 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1456 (or 1454 counting only the distinct ones).

The product of its (nonzero) digits is 2048, while the sum is 26.

The square root of 840428 is about 916.7486023987. The cubic root of 840428 is about 94.3699020681.

The spelling of 840428 in words is "eight hundred forty thousand, four hundred twenty-eight".