212661 has 6 divisors (see below), whose sum is σ = 307190. Its totient is φ = 141768.

The previous prime is 212651. The next prime is 212669. The reversal of 212661 is 166212.

It is a happy number.

212661 is a `hidden beast` number, since 2 + 1 + 2 + 661 = 666.

It can be written as a sum of positive squares in only one way, i.e., 119025 + 93636 = 345^2 + 306^2 .

It is not a de Polignac number, because 212661 - 2¹⁴ = 196277 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (212669) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 11806 + ... + 11823.

2²¹²⁶⁶¹ is an apocalyptic number.

It is an amenable number.

212661 is a deficient number, since it is larger than the sum of its proper divisors (94529).

212661 is a wasteful number, since it uses less digits than its factorization.

212661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 23635 (or 23632 counting only the distinct ones).

The product of its digits is 144, while the sum is 18.

The square root of 212661 is about 461.1518188189. The cubic root of 212661 is about 59.6892264424.

Adding to 212661 its reverse (166212), we get a palindrome (378873).

It can be divided in two parts, 2126 and 61, that added together give a 7-th power (2187 = 3⁷).

The spelling of 212661 in words is "two hundred twelve thousand, six hundred sixty-one".