21622 has 8 divisors (see below), whose sum is σ = 34200. Its totient is φ = 10224.

The previous prime is 21617. The next prime is 21647. The reversal of 21622 is 22612.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a congruent number.

It is an unprimeable number.

21622 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 247 + ... + 322.

It is an arithmetic number, because the mean of its divisors is an integer number (4275).

2²¹⁶²² is an apocalyptic number.

21622 is a deficient number, since it is larger than the sum of its proper divisors (12578).

21622 is a wasteful number, since it uses less digits than its factorization.

21622 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 590.

The product of its digits is 48, while the sum is 13.

The square root of 21622 is about 147.0442110387. The cubic root of 21622 is about 27.8589848818.

Subtracting from 21622 its sum of digits (13), we obtain a square (21609 = 147²).

Subtracting 21622 from its reverse (22612), we obtain a triangular number (990 = T₄₄).

The spelling of 21622 in words is "twenty-one thousand, six hundred twenty-two".