212845 has 4 divisors (see below), whose sum is σ = 255420. Its totient is φ = 170272.

The previous prime is 212843. The next prime is 212851. The reversal of 212845 is 548212.

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 84681 + 128164 = 291^2 + 358^2 .

It is a cyclic number.

It is not a de Polignac number, because 212845 - 2¹ = 212843 is a prime.

212845 is a lucky number.

It is a nialpdrome in base 12.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (212843) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 21280 + ... + 21289.

It is an arithmetic number, because the mean of its divisors is an integer number (63855).

2²¹²⁸⁴⁵ is an apocalyptic number.

It is an amenable number.

212845 is a deficient number, since it is larger than the sum of its proper divisors (42575).

212845 is an equidigital number, since it uses as much as digits as its factorization.

212845 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 42574.

The product of its digits is 640, while the sum is 22.

The square root of 212845 is about 461.3512761443. The cubic root of 212845 is about 59.7064363863.

The spelling of 212845 in words is "two hundred twelve thousand, eight hundred forty-five".