21020120111 has 2 divisors, whose sum is σ = 21020120112. Its totient is φ = 21020120110.

The previous prime is 21020120087. The next prime is 21020120131. The reversal of 21020120111 is 11102102012.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21020120111 - 2²² = 21015925807 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21020120092 and 21020120101.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21020120131) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10510060055 + 10510060056.

It is an arithmetic number, because the mean of its divisors is an integer number (10510060056).

Almost surely, 2^21020120111 is an apocalyptic number.

21020120111 is a deficient number, since it is larger than the sum of its proper divisors (1).

21020120111 is an equidigital number, since it uses as much as digits as its factorization.

21020120111 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 8, while the sum is 11.

Adding to 21020120111 its reverse (11102102012), we get a palindrome (32122222123).

The spelling of 21020120111 in words is "twenty-one billion, twenty million, one hundred twenty thousand, one hundred eleven".