201221020 has 288 divisors, whose sum is σ = 624314880. Its totient is φ = 52462080.

The previous prime is 201221017. The next prime is 201221099. The reversal of 201221020 is 20122102.

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 = 201220988 and 201221006.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 8748729 + ... + 8748751.

It is an arithmetic number, because the mean of its divisors is an integer number (2167760).

Almost surely, 2^201221020 is an apocalyptic number.

201221020 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 201221020, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (312157440).

201221020 is an abundant number, since it is smaller than the sum of its proper divisors (423093860).

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

201221020 is a wasteful number, since it uses less digits than its factorization.

201221020 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 105 (or 80 counting only the distinct ones).

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

The square root of 201221020 is about 14185.2395115486. The cubic root of 201221020 is about 585.9912286541.

201221020 divided by its sum of digits (10) gives a palindrome (20122102).

Adding to 201221020 its reverse (20122102), we get a palindrome (221343122).

It can be divided in two parts, 2012 and 21020, that added together give a palindrome (23032).

The spelling of 201221020 in words is "two hundred one million, two hundred twenty-one thousand, twenty".