201721220 has 12 divisors (see below), whose sum is σ = 423614604. Its totient is φ = 80688480.

The previous prime is 201721199. The next prime is 201721231. The reversal of 201721220 is 22127102.

It can be written as a sum of positive squares in 2 ways, for example, as 114746944 + 86974276 = 10712^2 + 9326^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5043011 + ... + 5043050.

It is an arithmetic number, because the mean of its divisors is an integer number (35301217).

Almost surely, 2^201721220 is an apocalyptic number.

201721220 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

201721220 is an abundant number, since it is smaller than the sum of its proper divisors (221893384).

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

201721220 is a wasteful number, since it uses less digits than its factorization.

201721220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10086070 (or 10086068 counting only the distinct ones).

The product of its (nonzero) digits is 112, while the sum is 17.

The square root of 201721220 is about 14202.8595712272. The cubic root of 201721220 is about 586.4763838528.

Adding to 201721220 its reverse (22127102), we get a palindrome (223848322).

The spelling of 201721220 in words is "two hundred one million, seven hundred twenty-one thousand, two hundred twenty".