Christmas Puzzle - The First by MatriX

This puzzle will be revealed in stages. The first is a straightforward numerical puzzle whose finished grid will be transformed in due course. The conventions for the first stage are:
·    no answer or intermediate answer involves a zero start,
·    results of functions such as multiple, divisor, anagram, reverse differ from the original number,
·    all answers are unique.



Across
1    reverse(32a) – 21a
4    multiple(17a)
6    reverse(divisor(14a))
9    divisor(22a)
11    triangular
12    palindrome
14    ascending digits
16    triangular
17    reverse(7d)
19    square
21    square
22    ascending digits
26    multiple(6a)
28    see 27d
30    square – 24d
31    digital product(22a)
32    see 20d
33    anagram(square)		 Down
2    see 25d
3    multiple(10d)
4    multiple(digit sum(4a))
5    digit sum(12a)
6    square
7    triangular
8    square divisor(27d)
9    square – 9a
10    cube
13    1a + square
15    square
18    triangular
20    multiple(anagram(32a))
21    prime
23    triangular – reverse(30a)
24    see 30a
25    digital product(2d)
27    divisor(28a)
29    odd divisor(33a)
The Second part of this Christmas puzzle will be published on 14 December.