The math.isqrt() computes the integer square root of a number. 

The integer square root of a number is the greatest integer less than or equal to the exact square root of the number. For example, the exact square root of 20 is 4.47213595499958, therefore,  the integer square root of 20 is 4.

Syntax:
math.isqrt(x)

Where, parameter x is an integer whose square root is to be calculated.

ExampleEdit & Run
import math

print(math.isqrt(25))
print(math.isqrt(20))
print(math.isqrt(40))
print(math.isqrt(111))
print(math.isqrt(500))
print(math.isqrt(1000))
Output:
546102231[Finished in 0.010491826804354787s]

The argument given to math.isqrt() function should be strictly integer. Otherwise, a TypeError is raised.

ExampleEdit & Run
import math

math.isqrt(100.5)
Output:
Traceback (most recent call last):  File "<string>", line 3, in <module>TypeError: 'float' object cannot be interpreted as an integer[Finished in 0.010268079116940498s]