22681 has 4 divisors (see below), whose sum is σ = 23332. Its totient is φ = 22032.

The previous prime is 22679. The next prime is 22691. The reversal of 22681 is 18622.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 18622 = 2 ⋅9311.

It can be written as a sum of positive squares in 2 ways, for example, as 8281 + 14400 = 91^2 + 120^2 .

It is a cyclic number.

It is not a de Polignac number, because 22681 - 2¹ = 22679 is a prime.

It is a super-2 number, since 2×22681² = 1028855522, which contains 22 as substring.

It is a Duffinian number.

It is a plaindrome in base 16.

It is not an unprimeable number, because it can be changed into a prime (22621) 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 3 ways as a sum of consecutive naturals, for example, 270 + ... + 343.

It is an arithmetic number, because the mean of its divisors is an integer number (5833).

2²²⁶⁸¹ is an apocalyptic number.

22681 is the 81-st centered heptagonal number.

It is an amenable number.

22681 is a deficient number, since it is larger than the sum of its proper divisors (651).

22681 is an equidigital number, since it uses as much as digits as its factorization.

22681 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 650.

The product of its digits is 192, while the sum is 19.

The square root of 22681 is about 150.6021248190. The cubic root of 22681 is about 28.3065798982.

It can be divided in two parts, 22 and 681, that added together give a triangular number (703 = T₃₇).

The spelling of 22681 in words is "twenty-two thousand, six hundred eighty-one".