212689 has 4 divisors (see below), whose sum is σ = 216756. Its totient is φ = 208624.

The previous prime is 212683. The next prime is 212701. The reversal of 212689 is 986212.

It is a happy number.

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 166464 + 46225 = 408^2 + 215^2 .

It is a cyclic number.

It is not a de Polignac number, because 212689 - 2⁷ = 212561 is a prime.

It is a super-2 number, since 2×212689² = 90473221442, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (212683) 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 3 ways as a sum of consecutive naturals, for example, 1954 + ... + 2059.

It is an arithmetic number, because the mean of its divisors is an integer number (54189).

2²¹²⁶⁸⁹ is an apocalyptic number.

It is an amenable number.

212689 is a deficient number, since it is larger than the sum of its proper divisors (4067).

212689 is an equidigital number, since it uses as much as digits as its factorization.

212689 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4066.

The product of its digits is 1728, while the sum is 28.

The square root of 212689 is about 461.1821765853. The cubic root of 212689 is about 59.6918459871.

The spelling of 212689 in words is "two hundred twelve thousand, six hundred eighty-nine".