21674 has 4 divisors (see below), whose sum is σ = 32514. Its totient is φ = 10836.

The previous prime is 21673. The next prime is 21683. The reversal of 21674 is 47612.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 20449 + 1225 = 143^2 + 35^2 .

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

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, 5417 + ... + 5420.

2²¹⁶⁷⁴ is an apocalyptic number.

21674 is a deficient number, since it is larger than the sum of its proper divisors (10840).

21674 is a wasteful number, since it uses less digits than its factorization.

21674 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10839.

The product of its digits is 336, while the sum is 20.

The square root of 21674 is about 147.2209224261. The cubic root of 21674 is about 27.8813002309.

It can be divided in two parts, 2167 and 4, that multiplied together give a palindrome (8668).

The spelling of 21674 in words is "twenty-one thousand, six hundred seventy-four".