20211021021 has 8 divisors (see below), whose sum is σ = 26981259424. Its totient is φ = 13457398320.

The previous prime is 20211020969. The next prime is 20211021043. The reversal of 20211021021 is 12012011202.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 20211021021 - 2⁹ = 20211020509 is a prime.

It is a super-2 number, since 2×20211021021² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 20211020988 and 20211021006.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20211021091) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4151086 + ... + 4155951.

It is an arithmetic number, because the mean of its divisors is an integer number (3372657428).

Almost surely, 2^20211021021 is an apocalyptic number.

It is an amenable number.

20211021021 is a deficient number, since it is larger than the sum of its proper divisors (6770238403).

20211021021 is an equidigital number, since it uses as much as digits as its factorization.

20211021021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8307851.

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

Adding to 20211021021 its reverse (12012011202), we get a palindrome (32223032223).

The spelling of 20211021021 in words is "twenty billion, two hundred eleven million, twenty-one thousand, twenty-one".