21011020020221 has 16 divisors (see below), whose sum is σ = 27574270978560. Its totient is φ = 15510527423280.

The previous prime is 21011020020203. The next prime is 21011020020229. The reversal of 21011020020221 is 12202002011012.

It is a cyclic number.

It is not a de Polignac number, because 21011020020221 - 2⁶ = 21011020020157 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21011020020196 and 21011020020205.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21011020020229) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 7180798271 + ... + 7180801196.

It is an arithmetic number, because the mean of its divisors is an integer number (1723391936160).

Almost surely, 2^{21011020020221} is an apocalyptic number.

It is an amenable number.

21011020020221 is a deficient number, since it is larger than the sum of its proper divisors (6563250958339).

21011020020221 is a wasteful number, since it uses less digits than its factorization.

21011020020221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14361599504.

The product of its (nonzero) digits is 32, while the sum is 14.

Adding to 21011020020221 its reverse (12202002011012), we get a palindrome (33213022031233).

The spelling of 21011020020221 in words is "twenty-one trillion, eleven billion, twenty million, twenty thousand, two hundred twenty-one".