20211002021 has 6 divisors (see below), whose sum is σ = 23510757510. Its totient is φ = 17323715976.

The previous prime is 20211001981. The next prime is 20211002047. The reversal of 20211002021 is 12020011202.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 16833765025 + 3377236996 = 129745^2 + 58114^2 .

It is not a de Polignac number, because 20211002021 - 2¹⁸ = 20210739877 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 20211001993 and 20211002011.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20211002921) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 206234666 + ... + 206234763.

It is an arithmetic number, because the mean of its divisors is an integer number (3918459585).

Almost surely, 2^20211002021 is an apocalyptic number.

It is an amenable number.

20211002021 is a deficient number, since it is larger than the sum of its proper divisors (3299755489).

20211002021 is an equidigital number, since it uses as much as digits as its factorization.

20211002021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 412469443 (or 412469436 counting only the distinct ones).

The product of its (nonzero) digits is 16, while the sum is 11.

Adding to 20211002021 its reverse (12020011202), we get a palindrome (32231013223).

The spelling of 20211002021 in words is "twenty billion, two hundred eleven million, two thousand, twenty-one".