2001221100021 has 32 divisors (see below), whose sum is σ = 3140408251008. Its totient is φ = 1117554128640.

The previous prime is 2001221099921. The next prime is 2001221100037. The reversal of 2001221100021 is 1200011221002.

It is not a de Polignac number, because 2001221100021 - 2¹⁷ = 2001220968949 is a prime.

It is a super-2 number, since 2×2001221100021² (a number of 25 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2001221000021) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 3948526 + ... + 4426431.

It is an arithmetic number, because the mean of its divisors is an integer number (98137757844).

Almost surely, 2^{2001221100021} is an apocalyptic number.

It is an amenable number.

2001221100021 is a deficient number, since it is larger than the sum of its proper divisors (1139187150987).

2001221100021 is a wasteful number, since it uses less digits than its factorization.

2001221100021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8375541.

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

Adding to 2001221100021 its reverse (1200011221002), we get a palindrome (3201232321023).

The spelling of 2001221100021 in words is "two trillion, one billion, two hundred twenty-one million, one hundred thousand, twenty-one".