821045 has 4 divisors (see below), whose sum is σ = 985260. Its totient is φ = 656832.

The previous prime is 821039. The next prime is 821053. The reversal of 821045 is 540128.

821045 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 195364 + 625681 = 442^2 + 791^2 .

It is a cyclic number.

It is not a de Polignac number, because 821045 - 2⁸ = 820789 is a prime.

It is a super-2 number, since 2×821045² = 1348229784050, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 82100 + ... + 82109.

It is an arithmetic number, because the mean of its divisors is an integer number (246315).

2⁸²¹⁰⁴⁵ is an apocalyptic number.

It is an amenable number.

821045 is a deficient number, since it is larger than the sum of its proper divisors (164215).

821045 is a wasteful number, since it uses less digits than its factorization.

821045 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 164214.

The product of its (nonzero) digits is 320, while the sum is 20.

The square root of 821045 is about 906.1153348222. The cubic root of 821045 is about 93.6387599109.

The spelling of 821045 in words is "eight hundred twenty-one thousand, forty-five".