2001121221 has 32 divisors (see below), whose sum is σ = 3087849600. Its totient is φ = 1139271680.

The previous prime is 2001121217. The next prime is 2001121223. The reversal of 2001121221 is 1221211002.

It is a cyclic number.

It is not a de Polignac number, because 2001121221 - 2² = 2001121217 is a prime.

It is a super-2 number, since 2×2001121221² = 8008972282273061682, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 2001121197 and 2001121206.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2001121223) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 316075 + ... + 322343.

It is an arithmetic number, because the mean of its divisors is an integer number (96495300).

Almost surely, 2^2001121221 is an apocalyptic number.

It is an amenable number.

2001121221 is a deficient number, since it is larger than the sum of its proper divisors (1086728379).

2001121221 is a wasteful number, since it uses less digits than its factorization.

2001121221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6869.

The product of its (nonzero) digits is 16, while the sum is 12.

The square root of 2001121221 is about 44733.8934254554. The cubic root of 2001121221 is about 1260.1564475681.

Adding to 2001121221 its reverse (1221211002), we get a palindrome (3222332223).

The spelling of 2001121221 in words is "two billion, one million, one hundred twenty-one thousand, two hundred twenty-one".