201021220 has 12 divisors (see below), whose sum is σ = 422144604. Its totient is φ = 80408480.

The previous prime is 201021211. The next prime is 201021229. The reversal of 201021220 is 22120102.

It is an interprime number because it is at equal distance from previous prime (201021211) and next prime (201021229).

It can be written as a sum of positive squares in 2 ways, for example, as 33732864 + 167288356 = 5808^2 + 12934^2 .

It is a Harshad number since it is a multiple of its sum of digits (10).

It is a junction number, because it is equal to n+sod(n) for n = 201021197 and 201021206.

It is not an unprimeable number, because it can be changed into a prime (201021229) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5025511 + ... + 5025550.

It is an arithmetic number, because the mean of its divisors is an integer number (35178717).

Almost surely, 2^201021220 is an apocalyptic number.

201021220 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

201021220 is an abundant number, since it is smaller than the sum of its proper divisors (221123384).

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

201021220 is a wasteful number, since it uses less digits than its factorization.

201021220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10051070 (or 10051068 counting only the distinct ones).

The product of its (nonzero) digits is 16, while the sum is 10.

The square root of 201021220 is about 14178.1952307055. The cubic root of 201021220 is about 585.7972134360.

Adding to 201021220 its reverse (22120102), we get a palindrome (223141322).

The spelling of 201021220 in words is "two hundred one million, twenty-one thousand, two hundred twenty".