821345 has 16 divisors (see below), whose sum is σ = 1164288. Its totient is φ = 544320.

The previous prime is 821333. The next prime is 821377. The reversal of 821345 is 543128.

It is not a de Polignac number, because 821345 - 2⁴ = 821329 is a prime.

It is a Duffinian number.

It is a nialpdrome in base 16.

It is a self number, because there is not a number n which added to its sum of digits gives 821345.

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, 707 + ... + 1463.

It is an arithmetic number, because the mean of its divisors is an integer number (72768).

2⁸²¹³⁴⁵ is an apocalyptic number.

It is an amenable number.

821345 is a deficient number, since it is larger than the sum of its proper divisors (342943).

821345 is a wasteful number, since it uses less digits than its factorization.

821345 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 800.

The product of its digits is 960, while the sum is 23.

The square root of 821345 is about 906.2808615435. The cubic root of 821345 is about 93.6501633489.

The spelling of 821345 in words is "eight hundred twenty-one thousand, three hundred forty-five".