2001220020 has 60 divisors (see below), whose sum is σ = 6277906404. Its totient is φ = 533658240.

The previous prime is 2001220019. The next prime is 2001220027. The reversal of 2001220020 is 200221002.

It can be written as a sum of positive squares in 2 ways, for example, as 240746256 + 1760473764 = 15516^2 + 41958^2 .

It is a tau number, because it is divible by the number of its divisors (60).

It is a Harshad number since it is a multiple of its sum of digits (9).

It is a junction number, because it is equal to n+sod(n) for n = 2001219984 and 2001220011.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2001220027) by changing a digit.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 616041 + ... + 619280.

Almost surely, 2^2001220020 is an apocalyptic number.

2001220020 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

2001220020 is an abundant number, since it is smaller than the sum of its proper divisors (4276686384).

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

2001220020 is a wasteful number, since it uses less digits than its factorization.

2001220020 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1235342 (or 1235331 counting only the distinct ones).

The product of its (nonzero) digits is 16, while the sum is 9.

The square root of 2001220020 is about 44734.9977087291. The cubic root of 2001220020 is about 1260.1771859666.

Adding to 2001220020 its reverse (200221002), we get a palindrome (2201441022).

The spelling of 2001220020 in words is "two billion, one million, two hundred twenty thousand, twenty".