21021111001111 has 4 divisors (see below), whose sum is σ = 22638119539672. Its totient is φ = 19404102462552.

The previous prime is 21021111001069. The next prime is 21021111001141. The reversal of 21021111001111 is 11110011112012.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21021111001111 - 2¹³ = 21021110992919 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (13), and also a Moran number because the ratio is a prime number: 1617008538547 = 21021111001111 / (2 + 1 + 0 + 2 + 1 + 1 + 1 + 1 + 0 + 0 + 1 + 1 + 1 + 1).

It is a junction number, because it is equal to n+sod(n) for n = 21021111001091 and 21021111001100.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21021111001141) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 808504269261 + ... + 808504269286.

It is an arithmetic number, because the mean of its divisors is an integer number (5659529884918).

Almost surely, 2^{21021111001111} is an apocalyptic number.

21021111001111 is a deficient number, since it is larger than the sum of its proper divisors (1617008538561).

21021111001111 is a wasteful number, since it uses less digits than its factorization.

21021111001111 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1617008538560.

The product of its (nonzero) digits is 4, while the sum is 13.

Adding to 21021111001111 its reverse (11110011112012), we get a palindrome (32131122113123).

The spelling of 21021111001111 in words is "twenty-one trillion, twenty-one billion, one hundred eleven million, one thousand, one hundred eleven".