20021011021 has 6 divisors (see below), whose sum is σ = 22006565966. Its totient is φ = 18200919000.

The previous prime is 20021011019. The next prime is 20021011033. The reversal of 20021011021 is 12011012002.

It can be written as a sum of positive squares in only one way, i.e., 11787444900 + 8233566121 = 108570^2 + 90739^2 .

It is not a de Polignac number, because 20021011021 - 2¹ = 20021011019 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 20021010989 and 20021011007.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20021011051) 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, 82731330 + ... + 82731571.

Almost surely, 2^20021011021 is an apocalyptic number.

It is an amenable number.

20021011021 is a deficient number, since it is larger than the sum of its proper divisors (1985554945).

20021011021 is a wasteful number, since it uses less digits than its factorization.

20021011021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 165462923 (or 165462912 counting only the distinct ones).

The product of its (nonzero) digits is 8, while the sum is 10.

Adding to 20021011021 its reverse (12011012002), we get a palindrome (32032023023).

The spelling of 20021011021 in words is "twenty billion, twenty-one million, eleven thousand, twenty-one".