2001021212021 has 16 divisors (see below), whose sum is σ = 2238504520560. Its totient is φ = 1776003425280.

The previous prime is 2001021211927. The next prime is 2001021212083. The reversal of 2001021212021 is 1202121201002.

It can be written as a sum of positive squares in 8 ways, for example, as 55662964900 + 1945358247121 = 235930^2 + 1394761^2 .

It is a cyclic number.

It is not a de Polignac number, because 2001021212021 - 2¹⁸ = 2001020949877 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 2001021211987 and 2001021212005.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2001021212621) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 10921070 + ... + 11102783.

It is an arithmetic number, because the mean of its divisors is an integer number (139906532535).

Almost surely, 2^{2001021212021} is an apocalyptic number.

It is an amenable number.

2001021212021 is a deficient number, since it is larger than the sum of its proper divisors (237483308539).

2001021212021 is a wasteful number, since it uses less digits than its factorization.

2001021212021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 22024136.

The product of its (nonzero) digits is 32, while the sum is 14.

Adding to 2001021212021 its reverse (1202121201002), we get a palindrome (3203142413023).

The spelling of 2001021212021 in words is "two trillion, one billion, twenty-one million, two hundred twelve thousand, twenty-one".