scripting/awk help : awk sum output is not comming in regular format. Pls advise.

Hi Experts,

I am adding a column of numbers with awk , however not getting correct output:

# awk '{sum+=$1} END {print sum}' datafile
2.15291e+06

How can I getthe output like : 2152910

Thank you..

 
# awk '{sum+=$1} END {print sum}' datafile 
2.15079e+06

#cat datafile
36171
3832
1361
1229
56096
1629
4421
3654
118455
52231
51299
188963
55128
105351
1229
1606
109271
13050
150202
92293
1157
54625
163311
1253
45338
628891
1357
209511

awk '{sum+=$1} END {printf "%.f\n",sum}' datafile

Scrutinizer ,
nice ..working Thanks.

If all the numbers are integers, you can use %d (or %u if always positive) instead of %.f