212805 has 12 divisors (see below), whose sum is σ = 368940. Its totient is φ = 113472.

The previous prime is 212801. The next prime is 212827. The reversal of 212805 is 508212.

It can be written as a sum of positive squares in 2 ways, for example, as 31329 + 181476 = 177^2 + 426^2 .

It is not a de Polignac number, because 212805 - 2² = 212801 is a prime.

212805 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (212801) 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 11 ways as a sum of consecutive naturals, for example, 2320 + ... + 2409.

It is an arithmetic number, because the mean of its divisors is an integer number (30745).

2²¹²⁸⁰⁵ is an apocalyptic number.

It is an amenable number.

212805 is a deficient number, since it is larger than the sum of its proper divisors (156135).

212805 is a wasteful number, since it uses less digits than its factorization.

212805 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4740 (or 4737 counting only the distinct ones).

The product of its (nonzero) digits is 160, while the sum is 18.

The square root of 212805 is about 461.3079231923. The cubic root of 212805 is about 59.7026959381.

The spelling of 212805 in words is "two hundred twelve thousand, eight hundred five".