20201221021 has 24 divisors (see below), whose sum is σ = 22092684288. Its totient is φ = 18449532000.

The previous prime is 20201221003. The next prime is 20201221037. The reversal of 20201221021 is 12012210202.

It is a happy number.

It is not a de Polignac number, because 20201221021 - 2⁹ = 20201220509 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 20201220992 and 20201221010.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20201221081) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 3029431 + ... + 3036091.

It is an arithmetic number, because the mean of its divisors is an integer number (920528512).

Almost surely, 2^20201221021 is an apocalyptic number.

It is an amenable number.

20201221021 is a deficient number, since it is larger than the sum of its proper divisors (1891463267).

20201221021 is a wasteful number, since it uses less digits than its factorization.

20201221021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7001 (or 6982 counting only the distinct ones).

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

Adding to 20201221021 its reverse (12012210202), we get a palindrome (32213431223).

The spelling of 20201221021 in words is "twenty billion, two hundred one million, two hundred twenty-one thousand, twenty-one".