2001220021021 has 4 divisors (see below), whose sum is σ = 2155160022652. Its totient is φ = 1847280019392.

The previous prime is 2001220020949. The next prime is 2001220021103. The reversal of 2001220021021 is 1201200221002.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 1358635016025 + 642585004996 = 1165605^2 + 801614^2 .

It is a cyclic number.

It is not a de Polignac number, because 2001220021021 - 2³⁷ = 1863781067549 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (13), and also a Moran number because the ratio is a prime number: 153940001617 = 2001220021021 / (2 + 0 + 0 + 1 + 2 + 2 + 0 + 0 + 2 + 1 + 0 + 2 + 1).

It is a junction number, because it is equal to n+sod(n) for n = 2001220020992 and 2001220021010.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2001220061021) 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 3 ways as a sum of consecutive naturals, for example, 76970000796 + ... + 76970000821.

It is an arithmetic number, because the mean of its divisors is an integer number (538790005663).

Almost surely, 2^{2001220021021} is an apocalyptic number.

It is an amenable number.

2001220021021 is a deficient number, since it is larger than the sum of its proper divisors (153940001631).

2001220021021 is a wasteful number, since it uses less digits than its factorization.

2001220021021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 153940001630.

The product of its (nonzero) digits is 32, while the sum is 13.

Adding to 2001220021021 its reverse (1201200221002), we get a palindrome (3202420242023).

The spelling of 2001220021021 in words is "two trillion, one billion, two hundred twenty million, twenty-one thousand, twenty-one".