21010220121111 has 48 divisors (see below), whose sum is σ = 30834582522912. Its totient is φ = 12716165030400.

The previous prime is 21010220121101. The next prime is 21010220121113. The reversal of 21010220121111 is 11112102201012.

It is a happy number.

It is not a de Polignac number, because 21010220121111 - 2⁹ = 21010220120599 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21010220121113) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 390055321 + ... + 390109181.

It is an arithmetic number, because the mean of its divisors is an integer number (642387135894).

Almost surely, 2^{21010220121111} is an apocalyptic number.

21010220121111 is a deficient number, since it is larger than the sum of its proper divisors (9824362401801).

21010220121111 is a wasteful number, since it uses less digits than its factorization.

21010220121111 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 66564 (or 66551 counting only the distinct ones).

The product of its (nonzero) digits is 16, while the sum is 15.

Adding to 21010220121111 its reverse (11112102201012), we get a palindrome (32122322322123).

The spelling of 21010220121111 in words is "twenty-one trillion, ten billion, two hundred twenty million, one hundred twenty-one thousand, one hundred eleven".