21020202011111 has 4 divisors (see below), whose sum is σ = 21273457457112. Its totient is φ = 20766946565112.

The previous prime is 21020202011101. The next prime is 21020202011113. The reversal of 21020202011111 is 11111020202012.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21020202011111 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21020202011113) 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, 126627722876 + ... + 126627723041.

It is an arithmetic number, because the mean of its divisors is an integer number (5318364364278).

Almost surely, 2^{21020202011111} is an apocalyptic number.

21020202011111 is a deficient number, since it is larger than the sum of its proper divisors (253255446001).

21020202011111 is an equidigital number, since it uses as much as digits as its factorization.

21020202011111 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 253255446000.

The product of its (nonzero) digits is 16, while the sum is 14.

Adding to 21020202011111 its reverse (11111020202012), we get a palindrome (32131222213123).

The spelling of 21020202011111 in words is "twenty-one trillion, twenty billion, two hundred two million, eleven thousand, one hundred eleven".