201720220740 has 144 divisors (see below), whose sum is σ = 641162995200. Its totient is φ = 51237736704.

The previous prime is 201720220739. The next prime is 201720220747. The reversal of 201720220740 is 47022027102.

It is a super-2 number, since 2×201720220740² (a number of 23 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (201720220747) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 887526 + ... + 1091394.

It is an arithmetic number, because the mean of its divisors is an integer number (4452520800).

Almost surely, 2^201720220740 is an apocalyptic number.

201720220740 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 201720220740, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (320581497600).

201720220740 is an abundant number, since it is smaller than the sum of its proper divisors (439442774460).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

201720220740 is a wasteful number, since it uses less digits than its factorization.

201720220740 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 204146 (or 204141 counting only the distinct ones).

The product of its (nonzero) digits is 3136, while the sum is 27.

Adding to 201720220740 its reverse (47022027102), we get a palindrome (248742247842).

The spelling of 201720220740 in words is "two hundred one billion, seven hundred twenty million, two hundred twenty thousand, seven hundred forty".