21574 has 16 divisors (see below), whose sum is σ = 39168. Its totient is φ = 8712.

The previous prime is 21569. The next prime is 21577. The reversal of 21574 is 47512.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21577) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 289 + ... + 355.

It is an arithmetic number, because the mean of its divisors is an integer number (2448).

2²¹⁵⁷⁴ is an apocalyptic number.

21574 is a deficient number, since it is larger than the sum of its proper divisors (17594).

21574 is a wasteful number, since it uses less digits than its factorization.

21574 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 99.

The product of its digits is 280, while the sum is 19.

The square root of 21574 is about 146.8809041367. The cubic root of 21574 is about 27.8383543199.

It can be divided in two parts, 215 and 74, that added together give a square (289 = 17²).

The spelling of 21574 in words is "twenty-one thousand, five hundred seventy-four".