21676 has 6 divisors (see below), whose sum is σ = 37940. Its totient is φ = 10836.

The previous prime is 21673. The next prime is 21683. The reversal of 21676 is 67612.

It is a super-3 number, since 3×21676³ = 30553339211328, which contains 333 as substring.

It is an alternating number because its digits alternate between even and odd.

It is a nialpdrome in base 15.

It is not an unprimeable number, because it can be changed into a prime (21673) 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 as a sum of consecutive naturals, namely, 2706 + ... + 2713.

2²¹⁶⁷⁶ is an apocalyptic number.

It is an amenable number.

21676 is a deficient number, since it is larger than the sum of its proper divisors (16264).

21676 is a wasteful number, since it uses less digits than its factorization.

21676 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5423 (or 5421 counting only the distinct ones).

The product of its digits is 504, while the sum is 22.

The square root of 21676 is about 147.2277147822. The cubic root of 21676 is about 27.8821578004.

It can be divided in two parts, 216 and 76, that added together give a palindrome (292).

The spelling of 21676 in words is "twenty-one thousand, six hundred seventy-six".