820545 has 16 divisors (see below), whose sum is σ = 1432512. Its totient is φ = 397760.

The previous prime is 820541. The next prime is 820559. The reversal of 820545 is 545028.

It is not a de Polignac number, because 820545 - 2² = 820541 is a prime.

It is a Curzon number.

It is a nialpdrome in base 16.

It is not an unprimeable number, because it can be changed into a prime (820541) by changing a digit.

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, 2322 + ... + 2651.

It is an arithmetic number, because the mean of its divisors is an integer number (89532).

2⁸²⁰⁵⁴⁵ is an apocalyptic number.

It is an amenable number.

820545 is a deficient number, since it is larger than the sum of its proper divisors (611967).

820545 is a wasteful number, since it uses less digits than its factorization.

820545 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4992.

The product of its (nonzero) digits is 1600, while the sum is 24.

The square root of 820545 is about 905.8393897375. The cubic root of 820545 is about 93.6197480065.

The spelling of 820545 in words is "eight hundred twenty thousand, five hundred forty-five".