21020121112211 has 16 divisors (see below), whose sum is σ = 23969189409984. Its totient is φ = 18261409803264.

The previous prime is 21020121112157. The next prime is 21020121112217. The reversal of 21020121112211 is 11221112102012.

It is a cyclic number.

It is not a de Polignac number, because 21020121112211 - 2³⁴ = 21002941243027 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (17).

It is a self number, because there is not a number n which added to its sum of digits gives 21020121112211.

It is not an unprimeable number, because it can be changed into a prime (21020121112217) 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, 8876690 + ... + 10992536.

It is an arithmetic number, because the mean of its divisors is an integer number (1498074338124).

Almost surely, 2^{21020121112211} is an apocalyptic number.

21020121112211 is a deficient number, since it is larger than the sum of its proper divisors (2949068297773).

21020121112211 is a wasteful number, since it uses less digits than its factorization.

21020121112211 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2160830.

The product of its (nonzero) digits is 32, while the sum is 17.

Adding to 21020121112211 its reverse (11221112102012), we get a palindrome (32241233214223).

The spelling of 21020121112211 in words is "twenty-one trillion, twenty billion, one hundred twenty-one million, one hundred twelve thousand, two hundred eleven".