2001355220 has 24 divisors (see below), whose sum is σ = 4207950600. Its totient is φ = 799569792.

The previous prime is 2001355217. The next prime is 2001355229. The reversal of 2001355220 is 225531002.

It can be written as a sum of positive squares in 4 ways, for example, as 114147856 + 1887207364 = 10684^2 + 43442^2 .

It is a Harshad number since it is a multiple of its sum of digits (20).

It is a junction number, because it is equal to n+sod(n) for n = 2001355192 and 2001355201.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2001355229) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 43775 + ... + 76934.

It is an arithmetic number, because the mean of its divisors is an integer number (175331275).

Almost surely, 2^2001355220 is an apocalyptic number.

2001355220 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

2001355220 is an abundant number, since it is smaller than the sum of its proper divisors (2206595380).

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

2001355220 is a wasteful number, since it uses less digits than its factorization.

2001355220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 121547 (or 121545 counting only the distinct ones).

The product of its (nonzero) digits is 600, while the sum is 20.

The square root of 2001355220 is about 44736.5088043312. The cubic root of 2001355220 is about 1260.2055640089.

Adding to 2001355220 its reverse (225531002), we get a palindrome (2226886222).

The spelling of 2001355220 in words is "two billion, one million, three hundred fifty-five thousand, two hundred twenty".