840921 has 8 divisors (see below), whose sum is σ = 1180320. Its totient is φ = 531072.

The previous prime is 840911. The next prime is 840923. The reversal of 840921 is 129048.

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

It is not a de Polignac number, because 840921 - 2¹⁰ = 839897 is a prime.

It is a plaindrome in base 12.

It is a junction number, because it is equal to n+sod(n) for n = 840891 and 840900.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 840921.

It is not an unprimeable number, because it can be changed into a prime (840923) by changing a digit.

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, 7320 + ... + 7433.

It is an arithmetic number, because the mean of its divisors is an integer number (147540).

2⁸⁴⁰⁹²¹ is an apocalyptic number.

It is an amenable number.

840921 is a deficient number, since it is larger than the sum of its proper divisors (339399).

840921 is a wasteful number, since it uses less digits than its factorization.

840921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14775.

The product of its (nonzero) digits is 576, while the sum is 24.

The square root of 840921 is about 917.0174480347. The cubic root of 840921 is about 94.3883511074.

Adding to 840921 its reverse (129048), we get a palindrome (969969).

The spelling of 840921 in words is "eight hundred forty thousand, nine hundred twenty-one".